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Train and analyze a classifier

OpenAIMachine Learning Engineer · Technical Screen
MediumMachine Learning EngineerTechnical ScreenData Manipulation (SQL/Python)

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This question evaluates proficiency in end-to-end machine learning engineering, including exploratory data analysis, time-aware train/validation/test splitting, model baseline and improvement, class imbalance strategies, leakage-safe hyperparameter tuning, metric computation and calibration, error analysis, reproducible training pipelines with CLI/config/seed control, explainability (feature importance/SHAP and ablations), and documentation of risks, fairness checks and monitoring hooks. It is commonly asked to assess practical ability to manage the full ML lifecycle and data hygiene in production-like scenarios, testing applied Data Manipulation (SQL/Python) and Machine Learning competencies with an emphasis on practical application while also requiring conceptual understanding of evaluation, calibration and fairness.

Given a labeled dataset for binary classification, implement an end-to-end Python solution to train and analyze a classifier. Tasks: (

  1. perform EDA (missingness, outliers, leakage checks, target/feature drift over time), (
  2. create time-aware, stratified train/validation/test splits with proper cross-validation, (
  3. build a strong baseline and at least one improved model, (
  4. handle class imbalance (cost-sensitive loss, resampling, thresholds), (
  5. tune hyperparameters without leakage, (
  6. compute and compare metrics (ROC-AUC, PR-AUC, F1, calibration/Brier, confusion matrix at chosen threshold), (
  7. conduct error analysis by slice and feature, (
  8. produce a reproducible training script with CLI, config, and seed control, (
  9. explain feature importance/SHAP and validate with ablations, and (
  10. document risks, fairness checks, and monitoring hooks for production. Provide code snippets and explain your design choices.