Debug a model with data leakage
Last updated: February 10, 2026
Quick Overview
Your model shows poor recall. Walk through your debugging process and potential fixes.
Expedia
February 10, 20266
6
1,662 solved
Your model shows poor recall. Walk through your debugging process and potential fixes.
Expedia asks this during the Technical Screen to assess your depth in ML. They expect you to discuss the mathematical foundations, practical considerations, and common pitfalls when applying these techniques in production.
What the Interviewer Expects
- Explain the mathematical foundations with clarity
- Discuss practical implementation considerations and hyperparameter tuning
- Analyze the technique's strengths and weaknesses for different data types
- Demonstrate understanding of evaluation methodology and metrics
- Connect theory to real-world applications with concrete examples
Key Topics to Cover
How to Approach This
- Understand the bias-variance trade-off. High training accuracy but low test accuracy signals overfitting.
- Choose evaluation metrics carefully based on the problem. Accuracy alone is often insufficient.
- Feature engineering is often more impactful than model selection.
- Know when to use tree-based models (tabular data) vs neural networks (unstructured data).
- Handle class imbalance with SMOTE, class weights, or appropriate loss functions.
Possible Follow-up Questions
- When would you prefer a simpler model over a complex one?
- What regularization technique would you use and why?
- How would you handle a highly imbalanced dataset?
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Explore ML Interview PrepSample Answer
Core Concept: Data Leakage
Data leakage occurs when information from outside the training dataset is used to create the model, leading to overly optimistic performance estimates and poor generalization on unseen data. In the co...
How It Works: Identifying Leakage
To debug poor recall caused by data leakage, begin by understanding the data pipeline. Check for features that may inadvertently include future information or aggregate statistics that should not be a...
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