Analyst Handbook

Overview

Objective

The Analyst Handbook serves as a guide for analysts to perform exploratory data analysis and extract actionable insights using simple models within the xVector Platform. It also provides insights into orchestration and observability within data workflows. The handbook uses four business cases, tied to key modeling approaches (Regression, Classification, Clustering, and Time Series), to contextualize these concepts, with a focus on Marketing Analytics applications.

  • The first business case focuses on marketing campaigns and sales data. It uses linear regression to optimize marketing spend across different advertising channels and maximize sales revenue. The company's historical data on marketing campaigns and sales figures is explored to identify which channels provide the best ROI and determine the expected sales impact.
  • The second business case involves optimizing marketing strategies for a bank. It uses a random forest classification model to analyze bank marketing data to identify factors that drive campaign success and target customer segments that are most likely to respond positively.
  • The third business case aims to identify and understand customer segments based on purchasing behaviors. It uses KMeans clustering to analyze online retail transaction data to improve customer retention and maximize revenue by understanding customer segments and their purchasing behaviors.
  • The fourth business case involves analyzing and forecasting sales trends using store sales data. It uses an ARIMA time series model to identify peak sales periods, understand growth trends, and uncover seasonal patterns to optimize inventory, plan promotions, and enhance revenue predictability.

The handbook also provides information on evaluating metrics and model comparison. In addition, it includes a section on key components of data exploration and data snooping.

The business cases are taken from kaggle. In each of the scenarios, we will explore tools and techniques used to analyze data and gain business insights using the xVector Platform.

In-depth exploration of models or the creation of custom models will be addressed in the Data Scientist Handbook. Likewise, advanced enrichment functions and intricate data pipeline management will be covered in the Data Engineer Handbook.

xVector Platform Overview

xVector is a comprehensive platform for building data applications using a MetaGraph intelligence engine. It can not only help with exploring and analyzing data but also provide an end-to-end solution from connecting to data sources all the way to collaborating and analyzing data in a single pane. Here are more details describing the platform.

Our approach to solving business problems involves a structured workflow: first, connect to the data source and ingest the data into the platform. Next, explore the data and perform enrichment or cleaning as needed to ensure its quality and relevance. After preparing the data, it is passed through an appropriate model for detailed analysis. Once the pipeline is established, xVector enables observability through features like alerts for thresholds, anomaly detection, and drift monitoring. Additionally, xVector supports the ability to act on the gained insights via a write-back mechanism, allowing the enriched or updated data to be saved to a destination, such as an S3 bucket, as a new file for downstream use.

Business Case 1: Marketing Campaign and Sales Data

Marketing Campaign and Sales Data

Consider a business that would like to optimize marketing spend across different advertising channels to maximize sales revenue. This involves determining the effectiveness of TV, social media, radio, and influencer promotions in driving sales and understanding how to allocate budgets for the best return on investment (ROI).

The company has historical data available on the marketing campaigns, including budgets spent on TV, social media, radio, and influencer collaborations, alongside the corresponding sales figures. However, the question remains: how can the company predict sales more accurately, identify which channels provide the best ROI, and determine the expected sales impact per $1,000 spent?

This journey begins by exploring the data, which includes sales figures and promotional budgets across different channels. However, raw data is rarely in a usable form right from the start. To start off, we first address potential biases, handle missing values, and identify outliers that could distort the results, all while ensuring compliance with ethical standards for data use. With a clean and well-prepared dataset, the next step is to dive deeper into the data to extract meaningful insights.

To make informed decisions on marketing spend, businesses need to understand how each advertising channel influences sales. However, the relationship between marketing spend and sales is complex, with many factors at play. A natural approach for this type of analysis is to use a regression model. The choice of a regression model stems from its ability to predict continuous outcomes (in this case, sales) based on various input factors (such as TV, social media, radio, and influencer spend). By fitting a linear regression model to the data, we can estimate how changes in the marketing budget for each channel influence sales. This helps identify which channels yield the highest sales per dollar spent and provides a framework for making more informed budget allocation decisions. For instance, the model might show that spending on TV ads yields the highest return on investment, while spending on social media or radio could be less effective, guiding future budget allocations.

As the analysis progresses, the focus shifts from just identifying effective channels to ensuring the accuracy and reliability of the predictions. To achieve this, the model's performance is validated using key metrics like R² and Mean Squared Error. The R² score, in particular, indicates how well the model explains the variance in sales based on marketing spend, with a higher score suggesting that the model can predict sales more accurately. On the other hand, the Mean Squared Error (MSE) measures the average squared difference between predicted and actual sales, helping to assess the quality of the predictions—lower MSE values indicate a better fit of the model to the data.

By evaluating these metrics, businesses gain confidence in the model's ability to make reliable predictions. This validation process not only ensures that the insights are actionable but also provides a solid foundation for making informed budget adjustments. With these insights, companies can fine-tune their marketing strategies, reallocating budgets to the highest-performing channels and identifying areas where additional investment may not yield optimal results. This continuous feedback loop of analysis and adjustment is crucial for maintaining an ongoing, data-driven approach to marketing optimization, leading to more efficient spending and better long-term results.

Now, let us look at how all this can be achieved in the xVector Platform.

Dataset Overview

Marketing Campaign and Sales Data Source from kaggle is here.

  • TV promotion budget (in million)
  • Social Media promotion budget (in million)
  • Radio promotion budget (in million)
  • Influencer: Whether the promotion collaborate with Mega, Macro, Nano, Micro influencer
  • Sales (in million)
  • Analysis Questions
    • Which advertising channel provides the best ROI?
    • How accurately can we predict sales from advertising spend?
    • What's the expected sales impact per $1000 spent on each channel?

Importing Data

The first step to gaining insights into data is to bring the data from one or more data sources into the xVector Platform so you can enrich and analyze it. xVector has a rich catalogue of connectors, including the ability to develop custom connectors if required, which can be leveraged to connect to data sources to bring the data in. The following steps give you the ability to start this process in the xVector Platform:

  • Create a workspace by following the instructions here.
  • Access and process your data from various sources (files, databases, cloud storage) through an extensive library of connectors.
  • Here are step-by-step details to connect to data sources via the xVector Platform.
  • It is easy to add new connectors for future needs.

Understanding the Dataset

Once the data is imported, a copy of the dataset is created for enrichment purposes. xVector provides the capability to keep these datasets synchronized with the original data sources, ensuring consistency. Raw data is rarely in a usable form right from the start. It is important to understand the data generation process; identify potential biases or gaps in the data, preventing misinterpretation; identify preprocessing needs, such as handling missing values or outliers; and ensure compliance with data privacy and ethical standards, especially with sensitive information. xVector provides out-of-the-box tools to profile data and create reports, including GenAI-powered options, to explore and understand the data quickly and effectively. For deeper analysis, users can generate quick reports to explore further and uncover insights as needed.

In the current data set, as an example, we notice that there are very few missing values. Social media column has only six missing values out of around 4570 records. These records can either be removed or populated with average values or values provided by the business user from another system etc.. In the dataset, Influencer is a categorical value and there are 4 unique values for this column. These unique categorical values may need to be encoded to integers when implementing the model.

Data Enrichment also involves integrating additional information or transforming existing data to enhance its value and analytical potential. Here’s an example of how this dataset can be enriched:

  • Include a column indicating whether a campaign ran during a holiday season (e.g., Black Friday or Christmas). This helps analyze how sales are affected by holidays and whether holiday-specific campaigns are more effective.
  • Add metrics like the number of likes, shares, or comments on social media posts linked to a campaign. This helps us understand how audience interaction correlates with sales across different channels.

These are advanced enrichment functions that can be handled by Data Engineers as described in the Data Engineer Handbook (coming soon).

The platform offers intuitive tools for enriching the data, like the ability to join datasets to understand relationships (part of the Data Engineer Handbook), handle missing values, identify outliers that could distort the results, etc. The following steps help you navigate the xVector Platform to enrich and explore data:

To view the data profile page, click on the ellipses -> ”View Profile” on the copied dataset (tile with green spot below). Users can identify outliers, anomalies, correlations, and several other insights in this step.

  • Create additional reports to explore data further. Here are the steps.
  • Once you perform basic exploration of data, you can then enrich the data using the enrichment feature here. It is under the Dataset section in the document.
  • A sample of the join function is below. An advanced enrichment function is typically handled by Data Engineers and is described further in the Data Engineer Handbook:

GenAI: xVector Platform is layered with GenAI at various points. One can get a first draft of reports by clicking on the ellipses on the dataset (tile with green icon) and then on “Generate Exploratory Report” or “Generate Report’ as shown below:

Maximizing Sales Revenue

In the current case, the business would like to optimize marketing spend across different advertising channels to maximize sales revenue. Some of the questions the business would like answered are:

  • Which advertising channel provides the best ROI?
  • How accurately can we predict sales from advertising spend?
  • What's the expected sales impact per $1000 spent on each channel?

A natural approach for this type of analysis is to use a regression model. The choice of a regression model stems from its ability to predict continuous outcomes (in this case, sales) based on various input factors (such as TV, social media, radio, and influencer spend).

Implementing the Solution

To analyze the data and make predictions, we can build an xVector Data App with a linear regression model. Here are the steps to build the app

  • Create a linear regression model based on steps here. You will use parameters and evaluation metrics mentioned below.
  • Here is the model implemented in xVector. This gives the visibility into the parameters used, metrics and scores for analysis.

Analysis

Having implemented the Data App using the Linear Regression model, let us now derive insights for some of the questions the business wants answered.

Which advertising channel provides the best ROI?

  • The channel with the highest positive coefficient in the regression model has the greatest impact on sales per dollar spent.
  • Use the coefficients DataFrame to determine this.
  • In the above example, TV provides the best ROI as TV has the max. coefficient of 3.29.

This can also be inferred from the correlation matrix in the profile page of the dataset. In this case TV has the maximum correlation which is 0.99

How accurately can we predict sales from advertising spend?

  • The R² score measures the proportion of variance in sales explained by advertising spend. Closer to 1 implies high accuracy.
    • In the above example, it is quite accurate as R² score is 0.98
  • The Mean Absolute Error (MAE) quantifies the average error between actual and predicted sales. A lower MAE indicates that the model's predictions are closer to the actual values. A higher MAE indicates larger errors and a poorer fit of the model to the data.
    • Mean Absolute Error is 4.18, which is low implying the predictions are closer to the actual values.
  • Here is the link in the xVecto App that shows MAE and other scores:

What's the expected sales impact per $1000 spent on each channel?

  • Use the Impact per $1000 column from the coefficients DataFrame.
  • The coefficient of TV is 3.2938. This predicts that spending $1000 more on TV ads is expected to increase sales by $3293.8.

Negative Coefficients

  • A negative coefficient suggests an inverse relationship between the corresponding feature and the outcome variable. Specifically,
    • Influencer (-0.1142): Spending $1000 on Micro-Influencers reduces the outcome by roughly $114.20.

Possible Explanations for Negative Impacts

  • Diminishing Returns: These marketing channels might already be saturated, leading to diminishing or negative returns on additional investment.
  • Ineffective Strategy: The investment in these areas may not be optimized, or the target audience might not respond well to these channels.
  • Indirect Effects: The spending might be cannibalizing other channels or producing unintended negative outcomes (e.g., customer annoyance, ad fatigue).
  • Model Noise or Multicollinearity: If features are highly correlated (e.g., spending overlaps across channels), the coefficients can become less reliable and appear negative.

Positive vs. Negative Coefficients

  • Positive coefficients (e.g., TV and Influencer_Mega) imply that spending in those areas correlates with an increase in the predicted outcome.
  • Negative coefficients highlight areas where spending could potentially reduce returns, signaling a need to reevaluate or redistribute the marketing budget.

Parameters

Parameters are the configuration settings or external controls of a machine learning model that are set before training and cannot be learned directly from the data. They govern how the model learns, operates, and performs, influencing the training process and the resulting model's performance.

Proper parameter tuning can mean the difference between a mediocre and a high-performing model. It ensures the model generalizes well to unseen data, avoids overfitting or underfitting, and delivers actionable insights with precision.

The link here gives the parameters for Linear Regression from scikit-learn.

Below are some commonly used parameters depending on the model used:

Model Parameter Description Usage
Linear Regression fit_intercept Whether to calculate the intercept for the regression model. Set False if the data is already centered.
Normalize Normalizes input features. Deprecated in recent Scikit-learn versions. Helps with features on different scales.
test_size Size of test data Helps with splitting train and test data
Ridge Regression alpha L2 regularization strength. Larger values shrink coefficients more. Prevents overfitting by reducing model complexity.
solver Optimization algorithm: auto, saga, etc. Impacts convergence speed and stability for large datasets.
Lasso Regression alpha L1 regularization strength. Controls sparsity of coefficients. Useful for feature selection.
max_iter Maximum iterations for optimization. Impacts convergence for large or complex datasets.
XGBoost (Regression) eta (learning rate) Step size for updating predictions. Lower values make learning slower but more robust.
max_depth Maximum depth of trees. Higher values can capture complex relationships but risk overfitting.
colsample_bytree Fraction of features sampled for each tree. Introduces randomness, reducing overfitting.

Evaluating Metrics

Evaluating metrics is critical in machine learning and data analysis because they provide a quantitative measure of how well a model performs. They allow us to assess the accuracy, reliability, and effectiveness of a model's predictions and help guide improvements in the model-building process. Without proper metrics, it would be difficult to determine if a model is suitable for solving the business problem at hand.

Regression models predict continuous values, so the metrics focus on measuring the difference between predicted and actual values.

Metric Description
Mean Absolute Error (MAE) Measures the average magnitude of errors without considering their direction. 
Formula: 

A lower MAE indicates better model performance. It’s easy to interpret but doesn’t penalize large errors as much as MSE.
Mean Squared Error (MSE) Computes the average squared difference between actual and predicted values.
Formula:

Penalizes larger errors more than MAE, making it sensitive to outliers.
Root Mean Squared Error (RMSE) Square root of MSE; represents errors in the same unit as the target variable.
Formula:

Balances interpretability and sensitivity to large errors.
R² Score (Coefficient of Determination) Proportion of variance explained by the model. 
Formula:

Values range from 0 to 1, where 1 means perfect prediction. Negative values indicate poor performance.
Adjusted R² Adjusts R² for the number of predictors in the model, by penalizing the addition of irrelevant features.
Formula:

Useful for comparing models with different number of predictors.
Mean Absolute Percentage Error (MAPE) Measures error as a percentage of actual values, making it scale-independent.
Formula:

Useful for scale-independent evaluation but struggles with very small actual values.

Acting on the Insights

Once we have analyzed the data and gained insights, xVector supports a write-back mechanism, allowing the enriched or updated data to be saved to a destination, such as an S3 bucket, as a new file for downstream use. Here are the steps to implement “Write Back” feature.

After running a Linear Regression model on the Marketing Campaign and Sales dataset, the key output is a set of coefficients that quantify the impact of each advertising channel - TV, social media, radio, and influencer marketing - on sales. These coefficients indicate the expected increase in sales for every $1,000 spent on a given channel, providing actionable insights into the return on investment (ROI) for each type of advertising. Additionally, the model outputs predictions for future sales based on hypothetical or planned ad spend scenarios, allowing businesses to forecast sales outcomes and optimize budget allocation. For example, if the model indicates that TV ads generate the highest ROI, the business can prioritize this channel in its future marketing strategy. The predictions and insights enable marketing teams to focus on high-performing channels, reduce ineffective spend, and better align resources with revenue-driving activities. These outputs can be sent to target systems which can then be operationalized by the Marketing teams.

Observing Data

xVector provides the ability to gain control with built-in observability: monitor everything, customize alerts, and stay on top of your data and models. Observability including alerts, drifts and anomalies are available on xVector. Here are the steps to set them up.

Below is a screenshot of where drifts can be seen when you click on the model tile on the workspace.

Observability in the current Marketing Campaign and Sales dataset focuses on ensuring data quality, model accuracy, and actionable operational insights. Data observability involves monitoring for missing or inconsistent values, such as incomplete spend data or unrealistic sales figures (e.g., zero sales with significant ad spend). It also includes detecting outliers that may distort the model, such as unusually high ad spend on a single channel. Model observability involves tracking the performance of the Linear Regression model using metrics like R² and Mean Squared Error (MSE) to validate how well the model explains sales variability and predicts outcomes. Residual analysis is critical for identifying patterns in prediction errors that could indicate model bias or unmet assumptions. By maintaining robust observability, businesses can ensure accurate forecasts, reliable insights, and continuous improvement in marketing strategies.

Business Case 2: Bank Marketing Dataset

Bank Marketing Dataset

Marketing campaigns are resource-intensive, and ensuring their success requires focusing efforts on customers who are most likely to respond. The objective is to maximize Term deposits from customers by optimizing marketing strategies. This can be done by identifying the factors that drive campaign success, understanding the overall campaign performance, and targeting customer segments most likely to respond positively. By doing so, the bank can increase the efficiency of its campaigns, reduce costs, and improve subscription rates for term deposits.

The journey begins by exploring the dataset, which contains customer demographics, past campaign data, and behavioral features such as job, education, and balance. However, raw data often requires preparation. This involves handling missing values and encoding categorical variables (e.g., marital status, education, job), balancing the dataset to address class imbalances (e.g., more "no" responses than "yes"), and analyzing distributions and outliers to ensure the data is clean and reliable.

This step ensures the dataset is ready for predictive modeling and minimizes potential biases.

To predict whether a customer will subscribe to a term deposit, we use the Random Forest classification model. This model is chosen for its ability to handle complex, non-linear relationships between features and the ability to provide feature importance rankings to identify the most influential predictors.

By training the Random Forest model, we can predict customer responses and gain actionable insights. For instance, the model might show that call duration, previous campaign outcome, and account balance are the strongest predictors of subscription likelihood.

By continuously validating and refining the model, the bank ensures its marketing campaigns remain data-driven, efficient, and impactful, leading to improved conversion rates and better resource allocation.

Now, let us understand and explore the dataset.

Dataset Overview

Bank Marketing Dataset Source from kaggle is here.

  • Analysis Questions
    • What factors best predict campaign success?
    • What's the overall campaign success rate? **

** To be done in the Data Scientist Handbook

Importing Data

The first step to gaining insights into data is to bring the data from one or more data sources into the xVector Platform so you can enrich and analyze it. xVector has a rich catalogue of connectors, including the ability to develop custom connectors if required, which can be leveraged to connect to data sources to bring the data in. Following steps give you the ability to start this process in the xVector Platform:

  • Create a workspace by following the instructions here. If you already have a workspace, you can use that.
  • Access and process your data from various sources (files, databases, cloud storage) through an extensive library of connectors.
  • Here are step-by-step details to connect to data sources via the xVector Platform.
  • It is easy to add new connectors for future needs.

Understanding the Data

Once the data is imported, a copy of the dataset is created for enrichment purposes. xVector provides the capability to keep these datasets synchronized with the original data sources, ensuring consistency. Raw data is rarely in a usable form right from the start. It is important to understand the data generation process; identify potential biases or gaps in the data, prevent misinterpretation; identify preprocessing needs, such as handling missing values or outliers; and ensure compliance with data privacy and ethical standards, especially with sensitive information. xVector provides out-of-the-box tools to profile data and create reports, including GenAI-powered options, to explore and understand the data quickly and effectively. For deeper analysis, users can generate quick reports to further explore and uncover insights as needed.

The Bank Marketing dataset includes 17 attributes, with features such as customer demographics (e.g., age, job, marital status, education), financial details (e.g., balance, loan, housing), and engagement data (e.g., previous campaign outcomes, duration of calls, and contact methods). The target variable, deposit, indicates whether the customer subscribed (yes or no). The age range for this dataset is between 18 and 95 with about 57% of them being married. This kind of analysis helps with understanding what kind of data we are dealing with.

The dataset can be enriched by including the customer’s lifetime value or total deposits over time. High-value customers may have different behaviors compared to low-value customers when responding to campaigns. These are advanced enrich functions that will be handled in the Data Engineer Handbook.

Data engineers also organize information by domain aligning data sets with business functions such as sales, marketing, or finance. They ensure optimal performance through efficient data modeling, indexing, partitioning, and scalable pipelines. These topics will be covered in the Data Engineering Handbook.

The platform offers intuitive tools for enriching the data, like ability to join datasets to understand relationships (part of Data Engineer Handbook), handle missing values, identify outliers that could distort the results etc.. If a feature has missing values, replacing them with the mean (average), median (middle value), or mode (most frequent value) ensures the dataset remains complete and usable. Imputation helps the model focus on meaningful relationships rather than being skewed by missing or extreme values. Enrichment functions like imputing values and dropping outliers ensure that the data is consistent and reliable, which helps the model generalize well rather than being overly influenced by anomalies or gaps in the data. Data engineering for reporting involves optimizing read/write access via partitioning and query optimization. These topics will be further discussed in the Data Engineer Handbook.

Following steps help you navigate the xVector Platform to enrich and explore data:

In order to view the data profile page, click on the ellipses -> ”View Profile” on the copied dataset (tile with green icon below). Users can identify outliers, anomalies, correlations and several other insights in this step.

Below is a sample screenshot of custom visualization to explore data created by a user.

Classification - Enrich

Extract features for advanced modeling with a rich set of data manipulation functions on both numerical and textual data. Here is the link to see the enrichment function in the xVector Platform.

DML Action - Join
  • Create additional reports to explore data further. Here are the steps.
  • Once you perform basic exploration of data, you can then enrich the data using the enrichment feature here. It is under the Dataset section in the document.

GenAI: xVector Platform is layered with GenAI at various points. One can get a first draft of reports by clicking on the ellipses on the dataset (tile with green icon) and then on “Generate Exploratory Report” or “Generate Report’ as shown below. Here are sample links to “Generate Report” and “Generate Exploratory Report” on xVector.

  • Below is a screenshot of a workspace with data source, reports, and models:
Workspace - Platform

Maximizing Term Deposit Subscriptions

In the current case, the bank would like to maximize customers’ Term deposit subscriptions by optimizing their Marketing campaigns for specific customer segments. Some of the questions the business would like answered are:

  • What factors best predict campaign success?
  • What's the overall campaign success rate? **
  • Which customer segments are most likely to respond positively? **

A natural approach for this type of analysis is to use a classification model. The choice of a classification model stems from its ability to handle complex, non-linear relationships between features and the ability to provide feature importance rankings to identify the most influential predictors.

Implementing the Solution

To answer the above questions, we can build an xVector Data App with a RandomForest classification model. Here are the steps to build the app

  • Create a RandomForest Classifier model based on steps here. You can use parameters and evaluation metrics mentioned below.
  • Here is the model implemented in xVector. This gives the visibility into the parameters used, metrics and scores for analysis.

Analysis

Having implemented the Data App using the Random Forest Classification model, let us now derive insights for some of the questions the business wants answered.

  • What factors best predict campaign success?

Feature importance from the Random Forest model reveals the most influential factors. In this case, the top 3 features are duration, balance, and age.

  • What's the overall campaign success rate? **

The proportion of deposit == 'yes' gives the success rate. Here, the overall Campaign Success Rate is 47.38%

  • Which customer segments are most likely to respond positively? **

Based on the heatmap below, those with management jobs and tertiary education are most likely to respond positively.

Heat map

** These will be discussed in the Data Scientist Handbook.

Notes:

  • The target column is the deposit for the above dataset, a categorical variable with values like yes and no.
  • After One-Hot Encoding, the column becomes deposit_yes (1 for yes and 0 for no).
  • Columns like job, marital, education, default, housing, loan, contact, month, and poutcome are categorical and need encoding.
  • One-Hot Encoding (pd.get_dummies) is used, with drop_first=True to avoid dummy variable traps.
  • After training the Random Forest Classifier, feature importance is calculated and displayed for the most significant predictors of campaign success.
  • The success rate is computed as the proportion of customers who responded positively (deposit == 'yes').
  • Segments are grouped by marital and education to find combinations with the highest proportion of positive responses

Parameters

Parameters are the configuration settings or external controls of a machine learning model that are set before training and cannot be learned directly from the data. They govern how the model learns, operates, and performs, influencing the training process and the resulting model's performance.

Proper parameter tuning can mean the difference between a mediocre and a high-performing model. It ensures the model generalizes well to unseen data, avoids overfitting or underfitting, and delivers actionable insights with precision.

The link here gives the parameters for Random Forest Classification from scikit-learn.

Below are some commonly used parameters depending on the model used:

Model Parameter Description Usage
Random Forest Classifier n_estimators Number of trees in the forest. Affects accuracy and training speed; larger forests usually perform better.
max_features Number of features to consider when splitting. Reduces overfitting and speeds up training.
bootstrap Whether to sample data with replacement. Improves diversity among trees.
Logistic Regression penalty Type of regularization: l1, l2, elasticnet, or none. Adds constraints to model coefficients to prevent overfitting.
solver Optimization algorithm: liblinear, saga, lbfgs, etc. Determines how the model is optimized, with some solvers supporting specific penalties.
C Inverse of regularization strength. Smaller values increase regularization. Balances bias and variance.
max_iter Maximum number of iterations for optimization. Ensures convergence for complex problems.
Support Vector Machine (SVM) C Regularization parameter. Smaller values create larger margins but may underfit. Controls the trade-off between misclassification and margin size.
kernel Kernel type: linear, rbf, poly, or sigmoid. Determines how data is transformed into higher dimensions.
gamma Kernel coefficient for non-linear kernels. Impacts the decision boundary for non-linear kernels like rbf or poly.
Decision Tree Classifier criterion Function to measure split quality: gini or entropy. Controls how splits are chosen (impurity vs. information gain).
max_depth Maximum depth of the tree. Prevents overfitting by restricting the complexity of the tree.
min_samples_split Minimum samples required to split a node. Ensures that nodes are not split with very few samples.
min_samples_leaf Minimum samples required in a leaf node. Prevents overfitting by ensuring leaves have sufficient data.
K-Nearest Neighbors (KNN) n_neighbors Number of neighbors to consider for classification. Affects granularity of classification; smaller values lead to more localized decisions.
weights Weighting function: uniform (equal weight) or distance (closer points have higher weight). Impacts how neighbors influence the prediction.
metric Distance metric: minkowski, euclidean, manhattan, etc. Defines how distances between data points are calculated.
Naive Bayes var_smoothing Portion of variance added to stabilize calculations. Prevents division by zero for features with very low variance.
XGBoost (Classification) objective Specifies the learning task: binary:logistic, multi:softprob, etc. Matches the classification type (binary or multiclass).
scale_pos_weight Balances positive and negative classes for imbalanced datasets. Essential for tasks like fraud detection where class imbalance is significant.
max_depth Maximum depth of trees. Higher values increase model complexity but risk overfitting.
eta (learning rate) Step size for updating predictions. Smaller values lead to slower, more accurate training.
gamma Minimum loss reduction required for further tree splits. Higher values make the model more conservative.

Evaluating Metrics

Evaluating metrics are critical in machine learning and data analysis because they provide a quantitative measure of how well a model performs. They allow us to assess the accuracy, reliability, and effectiveness of a model's predictions and help guide improvements in the model-building process. Without proper metrics, it would be difficult to determine if a model is suitable for solving the business problem at hand.

Classification models predict discrete labels, so the metrics measure the correctness of those predictions.

Metric Description
Accuracy Ratio of correct predictions to total predictions. Suitable for balanced datasets.
Formula:

Works well for balanced datasets but fails for imbalanced ones.
Precision Fraction of relevant instances among retrieved instances or fraction of true positive predictions among all positive predictions.
Formula:

High precision minimizes false positives.
Recall (Sensitivity) Fraction of actual positives that were correctly predicted.
Formula:

High recall minimizes false negatives.
F1 Score Harmonic mean of precision and recall. Useful for imbalanced datasets.
Formula:

Best suited for imbalanced datasets.
Confusion Matrix Tabular representation of true positives, true negatives, false positives, and false negatives. Helps visualize classification performance.
ROC-AUC Score Measures the trade-off between true positive rate (TPR) and false positive rate (FPR). It evaluates a classifier's ability to distinguish between classes at various thresholds.Higher AUC indicates better performance.
Log Loss (Cross-Entropy Loss) Quantifies the difference between predicted probabilities and actual class labels.
Formula:

Lower values indicate better probabilistic predictions.

Acting on Insights

Once we have analyzed the data and gained insights, xVector supports a write-back mechanism, allowing the enriched or updated data to be saved to a destination, such as an S3 bucket, as a new file for downstream use. Here are the steps to implement “Write Back” feature.

After running a Random Forest classification model on the Bank Marketing dataset, the output consists of predicted probabilities for whether each customer will subscribe to a term deposit (yes or no). This includes classification results for the current dataset as well as the probability scores indicating the likelihood of subscription for each customer. Additionally, the model generates feature importance rankings, identifying the most influential factors driving customer decisions, such as call duration, previous campaign outcomes, and account balance. These outputs can be sent to marketing campaign systems which can then be used to operationalize insights.

Observing Data

xVector provides the ability to gain control with built-in observability: monitor everything, customize alerts, and stay on top of your data and models. Observability including alerts, drifts and anomalies are available on xVector. Here are the steps to set them up.

Below is a screenshot of where drifts can be seen when you click on the model tile on the workspace.

Observability in the Bank Marketing dataset involves monitoring data quality, model performance, and operational effectiveness. Data observability ensures that inputs like customer demographics, account balances, and contact methods are complete, consistent, and free of anomalies, such as missing or erroneous values. For instance, call durations recorded as zero may require closer inspection to ensure data integrity. Model observability involves tracking the performance of the Random Forest classifier using metrics such as accuracy, precision, recall, and F1-score, along with monitoring class imbalance issues that could affect predictions. It also includes analyzing the stability of feature importance over time and detecting performance drift as customer behaviors evolve. Pipeline observability focuses on ensuring that synchronization processes and model inference run without delays or failures, enabling timely delivery of predictions to campaign teams. By maintaining robust observability, the bank can ensure high data quality, reliable predictions, and improved marketing outcomes.

Business Case 3: Online Retail Transaction Data

Online Retail Transaction Data

An online retail store would like to identify and understand customer segments based on purchasing behaviors to improve customer retention and maximize revenue. By distinguishing the most valuable customers, the company can create targeted marketing strategies, enhance loyalty programs, and optimize resource allocation to increase long-term profitability.

The Online Retail Transaction dataset includes transactional details such as invoice numbers, stock codes, product descriptions, quantities, invoice dates, and customer IDs, along with the country of purchase. The primary goal is to use this information to segment customers based on their purchase behavior and determine which segments represent the most valuable customers.

The analysis begins with data exploration and preparation, a critical step for ensuring accuracy and reliability. Since raw data often contains missing or inconsistent values, initial efforts focus on cleaning and enriching the dataset. This includes handling missing customer IDs, removing canceled transactions, identifying and addressing outliers, and ensuring that the data reflects accurate purchase behaviors. These steps are essential for creating a robust foundation for further analysis.

Once the data is cleaned, the focus shifts to determining the optimal number of groups for segmentation. This involves applying clustering algorithms, such as K-Means, and using evaluation techniques like the elbow method to identify the number of clusters that best represent the data. By plotting the within-cluster sum of squares (WCSS) against the number of clusters, the point where the WCSS begins to plateau provides insight into the ideal number of groups. This step ensures that the segmentation is both meaningful and interpretable, helping the business create actionable strategies based on the identified groups.

The final step is to analyze the features that are most important for grouping or segmenting the dataset. Feature importance analysis helps prioritize the variables that have the strongest impact on segmentation. For example, transaction frequency, average spending, or specific product categories purchased may emerge as key drivers of customer behavior. By examining these features, the business can gain deeper insights into what differentiates one customer group from another and tailor their strategies accordingly.

This approach enables the business to make data-driven decisions about customer segmentation without relying solely on predefined frameworks. By addressing outliers, determining the optimal number of groups, and focusing on key features, the business can build robust customer profiles and implement targeted strategies that enhance customer engagement and drive revenue growth. The process also provides a foundation for continuously refining segmentation strategies as new data becomes available.

Let us now explore and analyze the dataset in the xVector Platform.

Dataset Overview

Online Retail Transaction Data Source from kaggle is here.

Analysis Questions

  • Are there outliers in the data points?
  • What should be the number of groups to segment the data points?
  • What are the important features to consider while grouping or segmenting dataset?

Importing Data

The first step to gaining insights into data is to bring the data from one or more data sources into the xVector Platform so you can enrich and analyze it. xVector has a rich catalogue of connectors, including the ability to develop custom connectors if required, which can be leveraged to connect to data sources to bring the data in. Following steps give you the ability to start this process in the xVector Platform:

  • Create a workspace by following the instructions here. If you already have a workspace, you can use that.
  • Access and process your data from various sources (files, databases, cloud storage) through an extensive library of connectors.
  • Here are step-by-step details to connect to data sources via the xVector Platform.
  • It is easy to add new connectors for future needs.

Understanding the Data

Once the data is imported, a copy of the dataset is created for enrichment purposes. xVector provides the capability to keep these datasets synchronized with the original data sources, ensuring consistency. Raw data is rarely in a usable form right from the start. It is important to understand the data generation process; identify potential biases or gaps in the data, preventing misinterpretation; identify preprocessing needs, such as handling missing values or outliers; and ensure compliance with data privacy and ethical standards, especially with sensitive information. xVector provides out-of-the-box tools to profile data and create reports, including GenAI powered options, to explore and understand the data quickly and effectively. For deeper analysis, users can generate quick reports to further explore and uncover insights as needed.

The Online Retail Transaction dataset contains records of customer purchases, including invoice numbers, stock codes, product descriptions, quantities, invoice dates, customer IDs, and the countries of purchase. It provides valuable insights into customer behavior and purchasing patterns, making it ideal for segmentation and sales analysis. There are several records with negative quantity which are not valid values. The invoices range between December 2010 and December 2011. Around 500K records belong to United Kingdom, this being the country with maximum records.

To enrich this dataset, additional features can be derived or integrated. For example, adding temporal features like the day of the week or whether the transaction occurred during a holiday season can reveal purchasing trends. Including geographic or demographic data, such as regional economic indicators or customer profiles, can help analyze differences in purchasing behaviors across locations or customer types. Behavioral metrics like average purchase frequency or recency can be calculated to better segment customers into meaningful groups. These enrichments not only improve the analytical depth of the dataset but also enhance the effectiveness of clustering models for customer segmentation and business decision-making. These will be handled by Data Engineers using techniques mentioned in the Data Engineer Handbook.

The platform offers intuitive tools for enriching the data, like the ability to join datasets to understand relationships, handle missing values, identify outliers that could distort the results, etc. Advanced enrich functions like joins will be handled by Data Engineers as described in the Data Engineer Handbook. The following steps help you navigate the xVector Platform to enrich and explore data:

  • In order to view the data profile page, xVector provides a profile page by clicking on the ellipses -> ”View Profile” on the copied dataset (tile with green icon below). Users can identify outliers, anomalies, correlations, and several other insights in this step.

Extract features for advanced modeling with a rich set of data manipulation functions on both numerical and textual data. Here is the link to see the enrichment function in the xVector Platform.

DML Action - Join
  • Create additional reports to explore data further. Here are the steps.
  • Once you perform basic exploration of data, you can then enrich the data using the enrichment feature here. It is under the Dataset section in the document.

GenAI: xVector Platform is layered with GenAI at various points. One can get a first draft of reports by clicking on the ellipses on the dataset (tile with green icon) and then on “Generate Exploratory Report” or “Generate Report’ as shown below. Here are sample links to “Generate Report” and “Generate Exploratory Report” on xVector.

  • Below is a screenshot of a workspace with data source, reports, and models:

Customer Segmentation to Maximize Revenue

An online retail store would like to identify and understand customer segments based on purchasing behaviors to improve customer retention and maximize revenue. By distinguishing the most valuable customers, the company can create targeted marketing strategies, enhance loyalty programs, and optimize resource allocation to increase long-term profitability. Some of the questions the store would like answered are:

  • Are there outliers in the data points?
  • What should be the number of groups to segment the data points?
  • What are the important features to consider while grouping or segmenting dataset?

The K-Means clustering model is ideal for the Online Retail Transaction dataset as it effectively segments customers into meaningful groups based on their purchasing behavior, uncovering patterns in the data. It is computationally efficient, scalable, and can handle unlabeled data, making it perfect for identifying customer segments like high-value or frequent buyers. Additionally, it helps detect outliers, determine the optimal number of groups, and prioritize key features for actionable insights.

Implementing the Solution

We can build an xVector Data App with KMeans Clustering model. Here are the steps to build the app

  • Use the workspace created here
  • Create a KMeans clustering model based on steps here. You will use parameters and evaluation metrics mentioned below.

Here is an example of clustering model implemented in xVector. This gives the visibility into the parameters used, metrics and scores for analysis. The dataset used for this implementation is electronics store data.

Analysis

  • Are there any outliers in the data points?

Using KMeans clustering, we can detect unusual patterns in transaction amounts or quantities that could signal fraud, unusual buying patterns, or even logistical errors. Outliers in the clusters can be flagged for further investigation or action.

In the current dataset, we only see a very sparse set of datapoints that are outliers.

Here are the segmentations as seen in the below screenshot:

How many optimal groups can the data points be categorized into so we can make business decisions around these groups?

In the current scenario, based on the below plot, we can have 3 groups.

What are the main features we should consider for the grouping?

The above plot indicates that stockcode and country should be considered as the main features while grouping to make business decisions.Analyst Handbook - Elbow Method

Parameters

Parameters are the configuration settings or external controls of a machine learning model that are set before training and cannot be learned directly from the data. They govern how the model learns, operates, and performs, influencing the training process and the resulting model's performance.

Proper parameter tuning can mean the difference between a mediocre and a high-performing model. It ensures the model generalizes well to unseen data, avoids overfitting or under-fitting, and delivers actionable insights with precision.

The link here gives the parameters for KMeans clustering from scikit-learn.

Below are some commonly used parameters depending on the model used:

Model Parameter Description Usage
K-Means n_clusters Number of clusters to form. Controls the number of groups/clusters in the data.
init Initialization method for centroids: k-means++, random. k-means++ is better for convergence.
max_iter Maximum number of iterations to run the algorithm. Prevents infinite loops and ensures convergence.
tol Tolerance for convergence. Stops the algorithm when the centroids' movement is smaller than this value.
n_init Number of times the K-Means algorithm will be run with different centroid seeds. Ensures better centroids and better performance.
DBSCAN eps Maximum distance between two points to be considered neighbors. Determines cluster density.
min_samples Minimum number of points required to form a dense region (a cluster). Larger values lead to fewer but denser clusters.
metric Distance metric used for clustering: euclidean, manhattan, etc. Affects the way distances are calculated between points.
Agglomerative Clustering n_clusters Number of clusters to form. Specifies the number of clusters to form at the end of the clustering process.
linkage Determines how to merge clusters: ward, complete, average, or single. Affects how clusters are combined (Ward minimizes variance).
affinity Metric used to compute distances: euclidean, manhattan, cosine, etc. Affects the distance measure between data points during clustering.
K-Medoids n_clusters Number of clusters to form. Specifies the number of clusters (like K-Means but uses medoids).
metric Distance metric for pairwise dissimilarity. Defines the method for calculating pairwise distances between points.
max_iter Maximum number of iterations to run the algorithm. Ensures termination after a certain number of iterations.
Gaussian Mixture Model n_components Number of mixture components (clusters). Determines the number of Gaussian distributions (clusters).
covariance_type Type of covariance matrix: full, tied, diag, or spherical. Defines how the covariance of the components is calculated.
tol Convergence threshold. Stops iteration if log-likelihood change is smaller than tol.
max_iter Maximum number of iterations for the EM algorithm. Ensures the algorithm stops after a fixed number of iterations.

Evaluating Metrics

Evaluating metrics is critical in machine learning and data analysis because they provide a quantitative measure of how well a model performs. They allow us to assess the accuracy, reliability, and effectiveness of a model's predictions and help guide improvements in the model-building process. Without proper metrics, it would be difficult to determine if a model is suitable for solving the business problem at hand.

Clustering models are unsupervised, so metrics evaluate the quality of the clusters formed.

Metric Description
Silhouette Score Measures how well clusters are separated and how close points are within a cluster. Ranges from -1 to 1. Higher values indicate well-separated and compact clusters.
Davies-Bouldin Index Measures the average similarity ratio of each cluster with the most similar cluster. It measures intra-cluster similarity relative to inter-cluster separation. Lower is better. Evaluates compactness and separation of clusters.
Calinski-Harabasz Score Ratio of cluster separation to cluster compactness. Higher values indicate better-defined clusters.
Adjusted Rand Index (ARI) Compares the clustering result to a ground truth (if available).Adjusts for chance clustering.
Mutual Information Score Measures agreement between predicted clusters and ground truth labels. Higher values indicate better alignment.

Acting on Insights

Once we have analyzed the data and gained insights, xVector supports a write-back mechanism, allowing the enriched or updated data to be saved to a destination, such as an S3 bucket, as a new file for downstream use. Here are the steps to implement “Write Back” feature.

After applying a clustering model to the Online Retail dataset, the primary output is a segmentation of customers or transactions into distinct groups based on shared characteristics, such as purchasing behavior based on country, frequency, or monetary value. For example, the model might identify segments like high-value customers, occasional buyers, or dormant customers. Each cluster is accompanied by profiles that describe the key attributes of its members, such as average purchase frequency, total spending, or preferred product categories. These outputs can be operationalized by tailoring marketing strategies for each segment, such as offering exclusive deals to high-value customers or reactivation campaigns for dormant ones. Clusters can also guide inventory management by highlighting products that are popular within specific segments, ensuring stock levels align with customer preferences. By leveraging these insights, businesses can enhance customer satisfaction, improve engagement, and increase revenue through more targeted and effective decision-making. Both enriched data and customer segmentation information can be sent to target systems to operationalize insights. Segmentation can be carried forward through partitioning and visualization with breakdown dimensions. These topics will be handled in the Data Science and Enineer Handbooks.

Observing Data

xVector provides the ability to gain control with built-in observability: monitor everything, customize alerts, and stay on top of your data and models. Observability including alerts, drifts and anomalies are available on xVector. Here are the steps to set them up.

Below is a screenshot of where drifts can be seen when you click on the model tile on the workspace.

Observability in the Online Retail dataset when using clustering focuses on monitoring data quality, model performance, and the interpretability of clusters. Data observability involves identifying and addressing missing values (e.g., incomplete customer information), detecting outliers that could distort clusters (e.g., unusually high purchase amounts), and ensuring data consistency across features like invoice numbers or stock codes. Model observability tracks the stability and quality of clusters using metrics such as the Silhouette Score or Davies-Bouldin Index, ensuring that clusters are distinct and meaningful. It also involves monitoring for cluster drift, where changes in customer behavior over time may alter the characteristics of existing groups. Pipeline observability ensures that the clustering process runs smoothly by monitoring the synchronization of datasets with their sources and alerting for delays or inconsistencies. By maintaining robust observability, businesses can ensure that their clustering models remain accurate, relevant, and actionable in driving customer-centric strategies.

Business Case 4: Store Sales Data

Store Sales Data

A store would like to analyze and forecast sales trends to improve decision-making for store operations and marketing. Understanding sales dynamics is critical for effective inventory management, planning promotions, and predicting future sales performance. The primary focus of this analysis is to determine whether the data is stationary, identify trends or seasonal patterns, and explore peak sales periods while forecasting future sales.

The journey begins by exploring the dataset, which contains past customer data. However, raw data often requires preparation. This involves handling missing values, analyzing distributions and outliers to ensure the data is clean and reliable.

This step ensures the dataset is ready for predictive modeling and minimizes potential biases.

The analysis begins by examining the stationarity of the data, which is a critical prerequisite for time series modeling. Stationary data has consistent statistical properties over time, such as mean and variance, and is easier to model effectively. Once stationarity is addressed, the focus shifts to identifying trends and seasonal patterns in sales. The dataset is decomposed into its components - trend, seasonality, and residuals - using visualization techniques and statistical methods. This helps uncover long-term growth trends and recurring patterns that are vital for planning. For instance, the analysis may reveal that sales exhibit a steady upward trend over time with seasonal spikes during holidays or weekends. Peak sales periods are identified by observing these seasonal spikes, enabling businesses to align marketing efforts and inventory levels with high-demand periods.

The ARIMA time series model is employed to forecast future sales while accounting for these trends and patterns. ARIMA is chosen for its ability to handle both autoregressive (AR) and moving average (MA) components while incorporating differencing to make the data stationary.

As the model is trained and tested, it provides forecasts for future sales, helping businesses anticipate growth trends and seasonal variations. Key metrics such as Mean Absolute Error (MAE) and Root Mean Squared Error (RMSE) are used to validate the accuracy of the predictions and assess the model's performance. By analyzing the results, businesses can make informed decisions, such as preparing for peak demand periods or adjusting their strategies to capitalize on long-term growth trends.

This approach not only provides insights into the current state of sales but also equips businesses with the tools to predict and plan for the future. By leveraging the ARIMA model and exploring stationarity, trends, and seasonality, the analysis delivers actionable insights that drive better resource allocation, enhance inventory management, and optimize promotional strategies to achieve long-term success.

Let us now explore and analyze the dataset on xVector platform.

Dataset Overview

Store Sales Time Series Data from Kaggle is here.

  • Analysis Questions
    • Is data stationary?
    • Does it have trend or seasonality?
    • What are the peak sales periods?***
    • What's the overall sales growth trend?***
    • Are there clear seasonal patterns in sales?***

*** Note: Reports were created for this.

Importing Data

The first step to gaining insights into data is to bring the data from one or more data sources into the xVector Platform so you can enrich and analyze it. xVector has a rich catalogue of connectors, including the ability to develop custom connectors if required, which can be leveraged to connect to data sources to bring the data in. Following steps give you the ability to start this process in the xVector Platform:

  • Create a workspace by following the instructions here. If you already have a workspace, you can use that.
  • Access and process your data from various sources (files, databases, cloud storage) through an extensive library of connectors.
  • Here are step-by-step details to connect to data sources via the xVector Platform.
  • It is easy to add new connectors for future needs.

Understanding the Data

Once the data is imported, a copy of the dataset is created for enrichment purposes. xVector provides the capability to keep these datasets synchronized with the original data sources, ensuring consistency. Raw data is rarely in a usable form right from the start. It is important to understand the data generation process; identify potential biases or gaps in the data, preventing misinterpretation; identify preprocessing needs, such as handling missing values or outliers; and ensure compliance with data privacy and ethical standards, especially with sensitive information. xVector provides out-of-the-box tools to profile data and create reports, including GenAI powered options, to explore and understand the data quickly and effectively. For deeper analysis, users can generate quick reports to further explore and uncover insights as needed.

Store Sales dataset tracks the number of transactions per store on a given day. The current dataset has about 21K records that have about 1000 transactions per day in a given store. There are no missing values in this dataset.

The Store Sales Time Series dataset contains historical sales data for various stores, including details such as store IDs, dates, product categories, promotions, and holiday events. It is designed for time series forecasting and provides insights into trends, seasonality, and factors influencing sales. But these datasets are available as separate csv files. These sources are joined into one big table by the Data Engineers.

To enrich this dataset, additional features can be derived or integrated. For example, adding weather data, such as temperature or rainfall during the sales period, can help explain fluctuations in demand. Temporal features like day of the week, month, or holiday proximity can reveal patterns in sales seasonality. Incorporating economic indicators, such as inflation rates or consumer spending trends, provides additional context for understanding sales drivers. Finally, including promotional details, such as discounts or advertising spend during specific periods, can further refine the analysis. These enrichments enable businesses to uncover deeper insights into sales patterns and improve the accuracy of their forecasting models. Some of these are advanced enrichment functions that will be handled by the Data Engineers described in the Data Engineer Handbook.

Hierarchical time series forecasting involves predicting data across multiple levels of a hierarchy, such as geographic regions, product categories, or time periods, to capture trends and patterns effectively. It ensures consistency between levels by aligning forecasts so that lower-level predictions aggregate correctly to higher levels. For example, in retail, sales can be forecasted at the store level and aggregated to regional or national levels to optimize inventory. This topic will be handled further in the Data Engineer Handbook.

The platform offers intuitive tools for enriching the data, like the ability to join datasets to understand relationships, handle missing values, identify outliers that could distort the results, etc.

The following steps help you navigate the xVector Platform to enrich and explore data:

  • In order to view the data profile page, xVector provides a profile page by clicking on the ellipses -> ”View Profile” on the copied dataset (tile with green icon below). Users can identify outliers, anomalies, correlations, and several other insights in this step.

Extract features for advanced modeling with a rich set of data manipulation functions on both numerical and textual data. Here is the link to see the enrichment function in the xVector platform.

DML Action - Join
  • Create additional reports to explore data further. Here are the steps.
  • Once you perform basic exploration of data, you can then enrich the data using the enrichment feature here. It is under the Dataset section in the document.
  • GenAI: xVector Platform is layered with GenAI at various points. One can get a first draft of reports by clicking on the ellipses on the dataset (tile with green icon) and then on “Generate Exploratory Report” or “Generate Report’ as shown below. Here are sample links to “Generate Report” and “Generate Exploratory Report” on xVector.
  • Below is a screenshot of a workspace with data source, reports, and models:

In the current business case, a store would like to analyze and forecast sales trends to improve decision-making for store operations and marketing. Understanding sales dynamics is critical for effective inventory management, planning promotions, and predicting future sales performance. The store would specifically like the following questions answered:

  • Is the data stationary?
  • Does it have a trend or seasonality?
  • What are the peak sales periods?***
  • What's the overall sales growth trend?***
  • Are there clear seasonal patterns in sales?***

ARIMA is popular for time series modeling because it can handle both stationary and non-stationary data through its three components: Autoregression (using past values), Integration (making data stationary), and Moving Average (accounting for error terms). It effectively captures trends, cycles, and random variations in time series data while providing statistically sound forecasts. Given these, the natural choice of the model is ARIMA here.

Implementing the Solution

We can build an xVector Data App with ARIMA Time Series model. Here are the steps to build the app

  • Create a Time Series model based on steps here. You will use parameters and evaluation metrics mentioned below.
  • Here is an example of timeseries model implemented in xVector. This gives the visibility into the parameters used, metrics and scores for analysis. The dataset used for this implementation is the sales data of a store .

Analysis

  • Is data stationary?

Based on the above analysis, the dataset is non-stationary. This implies that the data shows trends, seasonality, or varying variance over time.

  • Does it have trend or seasonality?

Based on the data distribution seen in the visualization of the model, we can infer that there is trend and seasonality:

The autocorrelation function (ACF) and partial autocorrelation function (PACF) plots help in understanding the temporal dependencies in the data.

  • Trend Detection with ACF: If the ACF plot shows a slow decay (i.e., it doesn’t drop off abruptly and stays correlated for a long time), this suggests the presence of a trend in the data. In this case, the data will need to be differenced.
    • If ACF shows slow decay, you likely have a trend in the data. In ARIMA, you'd need to apply differencing (the "I" component) to make the data stationary before modeling.
  • Seasonality Detection with ACF: If you notice spikes at regular intervals in the ACF plot (e.g., every 12 months, every 7 days), this indicates the presence of seasonality in the data. This would suggest the need for seasonal differencing or using a SARIMA model (Seasonal ARIMA).

  • What are the peak sales periods?***

December of every year has peak sales.

  • What's the overall sales growth trend?***
Sales Growth Trend
  • Are there clear seasonal patterns in sales?***
    • Holiday Patterns: Sales seem to peak in December (holiday season) and November (Black Friday).
    • Long-Term Trends: Seasonal patterns may change over time, indicating shifts in consumer behavior.
    • Overall Growth: The trend component will reveal whether the store's sales are growing, stagnating, or declining over time.
    • Below are the visualizations for the dataset

*** These will be discussed in the Data Scientist Handbook.

Seasonal Decomposition
Seasonality in Sales
Sales Forecast

Parameters

Parameters are the configuration settings or external controls of a machine learning model that are set before training and cannot be learned directly from the data. They govern how the model learns, operates, and performs, influencing the training process and the resulting model's performance.

Proper parameter tuning can mean the difference between a mediocre and a high-performing model. It ensures the model generalizes well to unseen data, avoids overfitting or underfitting, and delivers actionable insights with precision.

The link here gives the parameters for ARIMA Time Series from sktime.

The platform supports authoring algorithms which will be described further in the Data Scientist Handbook.

Below are some commonly used parameters depending on the model used:

Model Parameter Description Usage
ARIMA p Number of lag observations (autoregressive part). Captures dependency on past values.
d Degree of differencing to make the series stationary. Removes trends from the data.
q Number of lagged forecast errors (moving average part). Models dependency on past prediction errors.
SARIMA seasonal_order Tuple (P, D, Q, m) where m is the season length. Adds seasonal components to ARIMA.
trend Specifies long-term trend behavior: n (none), c (constant), or t (linear). Helps model global trends in data.
weekly_seasonality Whether to include weekly seasonality (True/False or int for harmonics). Useful for datasets with strong weekly patterns like retail sales.
XGBoost (for Time Series) max_depth Maximum depth of trees used for feature-based time series modeling. Captures complex temporal relationships.
eta (learning rate) Step size for updating predictions in gradient boosting. Lower values improve robustness but require more iterations.
colsample_bytree Fraction of features sampled for each tree. Reduces overfitting and adds diversity.
subsample Fraction of training instances sampled for each boosting iteration. Introduces randomness to prevent overfitting.
objective Learning task, e.g., reg:squarederror for regression tasks. Matches the regression nature of time series forecasting.
lambda L2 regularization term on weights. Controls overfitting by penalizing large coefficients.
alpha L1 regularization term on weights. Adds sparsity, which is helpful for feature selection.
booster Type of booster: gbtree, gblinear, or dart. Tree-based (gbtree) is most common for time series.
LSTM units Number of neurons in each LSTM layer. Higher values increase model capacity but risk overfitting.
input_shape Shape of input data (timesteps, features). Specifies the window of historical data and number of features.
return_sequences Whether to return the full sequence (True) or the last output (False). Use True for stacked LSTMs or sequence outputs.
dropout Fraction of neurons randomly dropped during training (e.g., 0.2). Prevents overfitting by adding regularization.
recurrent_dropout Fraction of recurrent connections dropped during training. Adds regularization to the temporal dependencies.
optimizer Algorithm for adjusting weights (e.g., adam, sgd). Controls how the model learns from errors.
loss Loss function (e.g., mse, mae, huber). Determines how prediction errors are minimized.
batch_size Number of sequences processed together during training. Smaller batches generalize better but take longer to train.
epochs Number of complete passes over the training dataset. Too many epochs may lead to overfitting.
timesteps Number of past observations used to predict future values. Determines the window of historical data analyzed for prediction.
Orbit response_col Name of the column containing the target variable (e.g., sales). Specifies which variable is being forecasted.
date_col Name of the column containing dates. Identifies the time index for forecasting.
seasonality Seasonal periods (e.g., weekly, monthly, yearly). Models seasonality explicitly, crucial for periodic patterns in time-series data.
seasonality_sm_input Number of Fourier terms used for seasonality approximation. Controls the smoothness of seasonality; higher values increase granularity.
level_sm_input Smoothing parameter for the level component (between 0 and 1). Determines how quickly the model adapts to recent changes in level.
growth_sm_input Smoothing parameter for the growth component. Adjusts the sensitivity of the growth trend over time.
estimator Optimizer used for parameter estimation (stan-map, pyro-svi, etc.). stan-map for faster optimization, pyro-svi for full Bayesian inference.
prediction_percentiles Percentiles for the uncertainty intervals (default: [5, 95]). Defines the confidence intervals for forecasts.
num_warmup Number of warmup steps in sampling (used in Bayesian methods). Higher values improve parameter estimation but increase computation time.
num_samples Number of posterior samples drawn (used in Bayesian methods). Ensures good posterior estimates; higher values yield more robust uncertainty estimates.
regressor_col Name(s) of columns used as regressors. Incorporates additional covariates into the model (e.g., holidays, promotions).

Evaluating Metrics

Time series models focus on predicting sequential data, so metrics measure the alignment of predicted values with the observed trend.

Metric Description
Mean Absolute Error (MAE) Ratio of correct predictions to total predictions. Suitable for balanced datasets and evaluates sequential data.
Formula:

Works well for balanced datasets but fails for imbalanced ones.
Mean Squared Error (MSE) Computes the average squared difference between actual and predicted values.
Formula:

Penalizes larger errors more than MAE, making it sensitive to outliers in time series.
Root Mean Squared Error (RMSE) Square root of MSE; represents errors in the same unit as the target variable. Evaluates prediction accuracy in the original scale of the data.
Formula:

Balances interpretability and sensitivity to large errors.
Mean Absolute Percentage Error (MAPE) Measures error as a percentage of actual values, making it scale-independent.
Formula:

Useful for scale-independent evaluation but struggles with very small actual values.
Symmetric Mean Absolute Percentage Error (sMAPE) Variant of MAPE, mitigates issues with small denominators.
Formula:
Dynamic Time Warping (DTW) Measures similarity between two-time series, even if they are misaligned.
R² Score Evaluates variance explained by the time series model
Formula:
.

Acting on Insights

Once we have analyzed the data and gained insights, xVector supports a write-back mechanism, allowing the enriched or updated data to be saved to a destination, such as an S3 bucket, as a new file for downstream use. Here are the steps to implement “Write Back” feature.

The predicted sales values for future dates, typically on a daily, weekly, or monthly basis are the output of the applied model. This data can be sent to target systems which can be used to operationalize the insights. For instance, higher forecasted sales during the holiday season may prompt increased stock levels or promotions.

Observing Data

xVector provides the ability to gain control with built-in observability: monitor everything, customize alerts, and stay on top of your data and models. Observability including alerts, drifts and anomalies are available on xVector. Here are the steps to set them up.

Below is a screenshot of where drifts can be seen when you click on the model tile on the workspace.

Observability in the Store Sales Time Series dataset ensures the quality, reliability, and efficiency of both data and models to deliver actionable forecasts. It begins with monitoring data quality by detecting missing values, outliers, or data drift that could impact results, ensuring the input data remains consistent and complete. Model observability focuses on tracking forecast accuracy using metrics like MAE, and RMSE while detecting parameter drift or confidence interval mismatches that may signal the need for re-tuning.

Summarization of the Data App

Summarization of the Data App

Typical Data App Process
Anatomy of a Data App
Anatomy

A Few Learning Principles

A Few Learning Principles

These principles are taken from “Learning from data”, a Caltech course by Yaser Abu-Mostafa: https://work.caltech.edu/telecourse

Occam's Razor

Prefer simpler models that adequately fit the data to reduce overfitting. Occam's Razor suggests that the simplest one that sufficiently explains the phenomenon is usually the best choice when faced with multiple explanations or solutions. Simplicity in this context means the solution with the fewest assumptions or components.

Bias and Variance

Bias and Variance are fundamental concepts in machine learning that describe errors introduced during the modeling process. Together, they form the bias-variance tradeoff, which helps explain a model's performance on training and testing data.

Bias

Bias is the error introduced by approximating a complex real-world problem with a simplified model.

  • A high-bias model makes strong assumptions about the data.
  • It typically underfits the data, failing to capture important patterns.
  • Examples: Linear models used for data with non-linear relationships.
  • Training Error: High bias leads to poor performance on the training dataset.
  • Test Error: The model performs poorly on new, unseen data because it has not learned the underlying structure of the data.

Variance

Variance measures the sensitivity of a model to small fluctuations in the training dataset.

  • A high-variance model is too complex and captures noise along with the signal.
  • It overfits the training data, memorizing details rather than generalizing patterns.
  • Examples: Deep neural networks trained on small datasets without regularization.
  • Training Error: Low variance results in very low error on training data because the model captures all details.
  • Test Error: High variance leads to poor performance on unseen data due to overfitting.

Bias-Variance Tradeoff

  • A good model needs to balance bias and variance:
    • High Bias, Low Variance: The model is simple, underfits the data, and lacks flexibility.
    • Low Bias, High Variance: The model is overly complex, overfits the training data, and fails to generalize.
    • Optimal Balance: A model that achieves low bias and low variance generalizes well to unseen data.
  • Visual Representation:
  • High Bias: Predictions are far from the target, but consistent.
  • High Variance: Predictions vary widely around the target.

Interpretation Guidelines during Analysis:

  • High Variance (Overfitting):
  • Training MSE very low
  • Test MSE much higher than training MSE
  • High cross-validation score standard deviation
  • Learning curves don't converge
  • High Bias (Underfitting):
  • Both training and test MSE are high
  • Low R-squared values
  • Learning curves are flat and high
  • Good Balance:
  • Similar training and test MSE
  • Moderate, consistent R-squared values
  • Converging learning curves
  • Low cross-validation score standard deviation

Data Snooping

Avoid tailoring models too closely to specific datasets through repeated testing. also known as data dredging or data fishing, refers to the inappropriate use of data to guide analysis, modeling, or hypothesis generation in a way that can lead to biased results. It occurs when the same dataset is used multiple times in different stages of the modeling process, including exploration, training, testing, and validation. This introduces data leakage and contaminates the results, undermining the model's ability to generalize to new data.

  • Inadvertently using test or validation data to influence model choices, leading to overly optimistic performance metrics.
  • Often a result of insufficient separation between training, validation, and test datasets.
  • Feature Selection: Choosing features based on how they perform on the test set.
  • Hyperparameter Tuning: Over-optimizing hyperparameters by repeatedly testing on the validation or test set.
  • Multiple Testing: Running many analyses and selectively reporting favorable results without accounting for randomness.
  • Overfitting: The model may fit noise or artifacts in the specific dataset rather than learning general patterns.
  • Misleading Performance Metrics: Results are biased, leading to inflated accuracy, precision, or recall metrics.
  • Inflated performance metrics can lead to the deployment of unreliable models, which may fail in production environments.
  • Results can lose credibility, especially in fields like finance or medicine, where the stakes are high.

Examples of Data Snooping

  • Feature Engineering with Test Data:
    • You compute a feature (e.g., mean sales per category) using the test data and use it during training. This introduces information from the test set, contaminating results.
  • Repeated Cross-Validation:
    • Running cross-validation multiple times with slight variations and picking the best-performing model based on the validation results.
  • Backtesting in Finance:
    • In financial models, adjusting strategies based on historical market data repeatedly can result in overfitting to past trends that may not generalize.

How to Avoid Data Snooping

  • Separate Data Properly:
    • Divide data into training, validation, and test sets with clear boundaries. Use the test set only for final evaluation.
  • Cross-Validation:
    • Use techniques like k-fold cross-validation to assess model performance without touching the test data.
  • Feature Engineering:
    • Perform feature engineering and selection using only the training data.
  • Holdout Dataset:
    • Keep a final holdout set untouched until the end to assess real-world performance.
  • Transparent Reporting:
    • Clearly document how data was used at each stage of the modeling process to ensure reproducibility.

Data snooping is a critical pitfall in machine learning, and careful experimental design and data handling is essential to prevent it and ensure reliable, unbiased model performance.

Below are more details around general exploration of data and models.

Key Components of Data Exploration

Key Components of Data Exploration

Let us look at the exploration of data in general. Exploring data (often called Exploratory Data Analysis or EDA) is a critical process of examining and understanding a dataset before diving into formal modeling or drawing conclusions.

  • Understanding the Data Generation Process
    • Providing critical context that ensures accurate and meaningful analysis
    • Aligning analysis with the purpose and conditions under which data was collected
    • Identifing potential biases or gaps in the data, preventing misinterpretation
    • Clarifying variable definitions and real-world relationships to improve assumptions and analysis accuracy
    • Helping identify preprocessing needs, such as handling missing values or outliers.
    • Ensuring compliance with data privacy and ethical standards, especially with sensitive information.
  • Initial Dataset Understanding
    • Checking the basic structure of the data
    • Identifying the number of rows and columns
    • Understanding data types (numeric, categorical, datetime)
    • Identifying missing values
    • Reviewing basic statistical summaries
  • Statistical Profiling
    • Calculating descriptive statistics across categorical and numerical data (mean, median, mode)
    • Computing standard deviation and variance
    • Understanding the distribution of variables
    • Identifying outliers and extreme values
    • Checking for skewness and kurtosis of numerical features
  • Visualization Techniques
    • Creating histograms to see data distribution
    • Using box plots to understand data spread and outliers
    • Generating scatter plots to see relationships between variables
    • Creating correlation matrices to understand feature interactions
    • Using heat maps to visualize complex data patterns
  • Data Quality Assessment
    • Detecting and handling missing values
    • Identifying duplicate records
    • Checking for data consistency
    • Verifying data integrity
  • Multivariate Analysis
    • Understanding correlations between different variables
    • Identifying potential predictive features
    • Checking multicollinearity
    • Exploring interactions between features
  • Hypothesis Generation
    • Forming initial insights about potential patterns
    • Developing questions for further investigation
    • Identifying potential modeling approaches

Data exploration is crucial because it:

  • Prevents incorrect assumptions
  • Guides feature engineering
  • Helps select appropriate modeling techniques
  • Reveals potential data quality issues
  • Provides initial insights into complex datasets

By thoroughly exploring data, data scientists create a solid foundation for more advanced analysis, machine learning modeling, and meaningful insights.

Model Comparison

Model Comparison

Xvector allows you to experiment, build, deploy, and monitor cutting-edge AI models for all your data science needs. Although we support several models, we will go over building regression, classification, clustering, and time series AI models on the xVector Platform with examples.

The key differences between these models are as follows:

Aspect Regression Classification Clustering Time Series
Purpose Predicts continuous numerical values. Assigns data points to categories (classes). Groups data points into clusters based on similarity. Predicts future values or trends based on time-ordered data.
Output Continuous values (e.g., house prices). Categorical labels (e.g., spam or not spam). Cluster labels (e.g., customer segments). Numerical or categorical predictions for future time points.
Type of Learning Supervised (labeled data). Supervised (labeled data). Unsupervised (no labels). Supervised or unsupervised, depending on context.
Algorithms Linear Regression, Gradient Boosting, Neural Networks. Logistic Regression, Decision Trees, SVM, Neural Networks. K-Means, DBSCAN, Hierarchical Clustering. ARIMA, LSTM, SARIMA, Prophet, XGBoost for time series.
Use Cases Price prediction, sales forecasting, stock prices. Fraud detection, image classification, medical diagnosis. Customer segmentation, anomaly detection. Forecasting sales, energy consumption, web traffic.
Data Type Labeled and numerical. Labeled and categorical. Unlabeled; numerical or categorical. Sequential, time-indexed data.

Notes:

  1. Simple Models: Use for interpretable, small datasets.
  2. Time Series Models: Handle trends, seasonality, and dependencies, with complexity increasing from statistical methods (e.g., ARIMA) to neural networks (e.g., LSTM).
  3. Advanced Neural Models: Best for high-dimensional or sequential tasks requiring context awareness.
  4. Specialized Models: Use clustering for unsupervised grouping, anomaly detection for rare event identification, and reinforcement learning for optimizing sequential decisions.

Selecting Appropriate Chart

Selecting Appropriate Chart

Chart Selection

Appendix

References

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