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Grab·Machine Learning Engineer·Onsite - Coding / Algorithms·Senior

SeniorPrefer not to say
Apr 2026

Summary

Grab ML engineer round that was basically a Kaggle problem live, which sounds stressful but the actual coding was offloaded to an AI agent so it was more about thinking out loud than typing fast. The real evaluation was on how you frame the problem, pick features, and reason about model choices.

Questions Asked (2)

Q1

Given pairs of point-of-interest records, how would you determine whether each pair refers to the same real-world location? Formulate this as an ML problem and walk through your approach end to end.

Technical Trade-offsData ModelingAlgorithms & Data Structures
Author's notes

The setup was a Kaggle link dropped in chat and then silence.

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AI HintsAI Generated

Suggested Approach

Frame it as a binary classification problem: given a pair of POI records, predict whether they refer to the same real-world location. Walk through data collection, feature engineering, model selection, evaluation, and deployment considerations, emphasizing the unique challenges of POI matching such as noisy text, geospatial proximity, and class imbalance.

Pro tip: Highlight the importance of a scalable blocking/indexing strategy to reduce the number of pairs to compare, and discuss how to handle ambiguous cases with human-in-the-loop validation. Also, mention that in production, you'd monitor for concept drift and retrain periodically.

1. Problem Formulation

Define the task as binary classification: output 1 if the pair refers to the same location, else 0. Discuss how to generate labeled data (e.g., from user feedback or manual annotation) and the need for a representative dataset.

2. Feature Engineering

Extract features from each POI record: textual (name, address, category), geospatial (latitude, longitude), and metadata (source, popularity). Compute similarity features between pairs: string similarity (Jaro-Winkler, Levenshtein), distance (Haversine), and categorical match.

3. Model Selection and Training

Choose a model suitable for tabular data with mixed features: gradient boosted trees (XGBoost, LightGBM) or a neural network with embeddings for text and geo. Address class imbalance via resampling or class weights. Use cross-validation and tune hyperparameters.

4. Evaluation and Thresholding

Evaluate using precision, recall, F1, and AUC-ROC, considering business costs of false positives vs. false negatives. Choose an operating threshold that balances precision and recall for the application (e.g., high precision for auto-merge, lower for human review).

5. Deployment and Scaling

Implement a blocking/indexing step to avoid O(n^2) comparisons: e.g., geohashing, inverted indexes on tokens. Deploy model as a service, with a feedback loop for continuous improvement. Monitor performance and retrain periodically.

Key Points to Mention

  • Class imbalance and how to handle it (e.g., SMOTE, class weights).
  • Feature engineering: string similarity metrics, geospatial distance, and categorical features.
  • Blocking/indexing to reduce candidate pairs (e.g., geohash, MinHash, inverted index).
  • Choice of evaluation metrics: precision, recall, F1, and business impact of errors.
  • Handling noisy and missing data (e.g., imputation, robust similarity measures).
  • Scalability and productionization: batch vs. real-time, monitoring, retraining.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.

Q2

How would you evaluate your deduplication model, and what metrics would you prioritize?

A/B Testing & ExperimentationProduct Analytics & Metrics
Author's notes

Precision vs recall tradeoff for entity matching is actually non-trivial and I think I handled it okay.

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AI HintsAI Generated

Suggested Approach

Start by clarifying the deduplication task (e.g., entity resolution, near-duplicate detection) and the business context (e.g., Grab's merchant or driver records). Then outline a multi-faceted evaluation strategy that combines offline metrics (precision, recall, F1) with online A/B testing, emphasizing the trade-off between false positives and false negatives. Finally, prioritize metrics based on business impact, such as reducing duplicate records while minimizing user friction.

Pro tip: Tie your metrics to Grab's key business outcomes—like reducing duplicate merchant listings to improve search relevance and driver allocation—and mention how you'd handle class imbalance and label noise in deduplication datasets.

1. Clarify the deduplication problem and business goals

Define what constitutes a duplicate (e.g., same entity with slight variations) and the cost of false positives vs. false negatives in Grab's context. Align evaluation with business objectives like data quality, user experience, and operational efficiency.

2. Select offline evaluation metrics

Choose metrics such as precision, recall, F1-score, and area under the precision-recall curve (AUPRC) due to class imbalance. Consider pairwise metrics (e.g., pair precision/recall) and cluster-level metrics (e.g., B-cubed) if deduplication outputs clusters.

3. Design online evaluation via A/B testing

Propose A/B tests measuring downstream impact: e.g., reduction in duplicate records, improvement in search ranking, or changes in user engagement. Define guardrail metrics to monitor unintended consequences.

4. Prioritize metrics based on business impact

Rank metrics by their alignment with Grab's goals: for example, prioritize precision if false merges harm user trust, or recall if missing duplicates degrades data quality. Use a weighted score or cost matrix to reflect trade-offs.

5. Monitor and iterate

Set up continuous monitoring for model drift and feedback loops. Use human-in-the-loop validation for ambiguous cases and retrain with new data to maintain performance.

Key Points to Mention

  • Precision, recall, F1-score, and AUPRC for offline evaluation, especially with imbalanced data.
  • Pairwise vs. cluster-level metrics (e.g., B-cubed) depending on deduplication output.
  • A/B testing with downstream business metrics (e.g., search relevance, conversion rates).
  • Cost-sensitive evaluation: false positives vs. false negatives and their business impact.
  • Handling label noise and creating a high-quality ground truth dataset.
  • Monitoring for model drift and incorporating human feedback.

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.