P80Feature EngineeringIntermediateDiagnose14 min

Diagnose Leakage From a Customer Lifetime Aggregate

Diagnose why a full-lifetime customer aggregate leaks future behavior into an earlier prediction.

#diagnose#leakage#aggregates

Scenario

A model predicts whether a customer will renew at day 30, but uses total_lifetime_spend calculated from the customer's entire account history.

Problem statement

Explain the leakage, why validation appears excellent, and how to rebuild the feature.

Your Task

  1. Identify information recorded after the prediction point.
  2. Contrast historical and full-lifetime aggregates.
  3. Define a valid replacement feature.

Related Concepts

Temporal leakageFeature availabilityPoint-in-time joins

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Mark it complete when you have reasoned through the solution in your own words.