Data Scientist Interview Questions

Showing 1711–1740 of 1971 results

• TikTokHard·Data Scientist
  Diagnose metric drop in Ads Manager

  This question evaluates a Data Scientist's competency in operational analytics, metric integrity, root-cause analysis, and experiment interpretation, covering concepts such as logging latency, sample ratio assessment, and product instrumentation awareness.

  Analytics & ExperimentationOnsite
• TikTokHard·Data Scientist
  Estimate heterogeneous treatment effects with causal ML

  This question evaluates a candidate's competency in causal machine learning, heterogeneous treatment effect estimation, off-policy evaluation, and fairness-aware policy design using observational data.

  Machine LearningTechnical Screen
• TikTokMedium·Data Scientist
  Explain Your Experience and Interest in Tech Role

  This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Explain Your Experience and Interest in Tech Role states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.

  Behavioral & LeadershipHR Screen
• TikTokHard·Data Scientist
  Explain and tune XGBoost; prevent overfitting

  This question evaluates understanding of XGBoost tree-boosting internals, hyperparameter impacts on bias/variance/training time, strategies for imbalanced binary classification and leakage-aware validation, post-training calibration, and interpretability for tabular fraud detection.

  Machine LearningTechnical Screen
• TikTokMedium·Data Scientist
  Explain your most impactful project trade-offs

  This question evaluates a data scientist's leadership, stakeholder management, quantitative impact measurement, trade-off analysis, risk mitigation, and conflict-resolution skills within end-to-end project work.

  Behavioral & LeadershipTechnical Screen
• TikTokEasy·Data Scientist
  Find top-paid employee per department

  This question evaluates a candidate's competency in SQL data manipulation, including aggregation, ranking, handling of duplicate and historical rows, tie semantics, and temporal data interpretation when determining the top-paid employee per department.

  Data Manipulation (SQL/Python)Technical Screen
• TikTokEasy·Data Scientist
  How do you choose a classification threshold?

  This question evaluates a data scientist's competency in binary classification threshold selection, end-to-end ML pipeline design, model evaluation, and operational trade-offs including class imbalance, asymmetric error costs, and limited escalation capacity, within the Machine Learning domain of model evaluation and deployment.

  Machine LearningTechnical Screen
• TikTokEasy·Data Scientist
  How would you measure misinformation impact and recommendation bias?

  This question tests the ability to design an evaluation framework for identifying algorithmic bias and measuring the reach of misinformation within a content recommendation system.

  Analytics & ExperimentationTechnical ScreenAnalyticsRecommendation SystemsMetrics
• TikTokMedium·Data Scientist
  Identify Repeat Advertisers from Consecutive Weeks

  This question evaluates a candidate's proficiency in manipulating relational data to identify recurring entities across consecutive time periods, focusing on SQL/Python data manipulation and temporal comparison of records.

  Data Manipulation (SQL/Python)Technical Screen
• TikTokMedium·Data Scientist
  Implement K-means and run two iterations

  This question evaluates understanding of k-means clustering concepts (k-means++ initialization, Lloyd iterations, and SSE) and proficiency in numerical implementation and vectorized array operations.

  Coding & AlgorithmsTechnical Screen
• TikTokMedium·Data Scientist
  Implement streaming SRM detector with late events

  This question evaluates proficiency in stateful stream processing, statistical anomaly detection for sample ratio mismatch, and scalable system design concerns such as deduplication, late/out-of-order event handling, real-time aggregation, chi-square testing with Yates correction, bot-rate mitigation, sharding, and replay validation.

  Coding & AlgorithmsHR Screen
• TikTokMedium·Data Scientist
  Improve TikTok's Algorithm for Diverse Content Discovery

  Evaluates product feedback and experiment design for improving content discovery in TikTok-style feeds. Strong answers propose specific improvements, justify impact, define metrics, and plan experiments with guardrails.

  Analytics & ExperimentationOnsite
• TikTokMedium·Data Scientist
  Investigate Traffic Distribution Impact on Retention Decrease

  Evaluates A/B test diagnostics for a retention decrease after a button-color change. Strong answers check allocation, balance, logging, maturation, statistical robustness, segments, and decision criteria before blaming treatment.

  Analytics & ExperimentationTechnical Screen
• TikTokHard·Data Scientist
  Investigate visit–report correlation causality

  This question evaluates a candidate's competency in causal inference, experimental design, diagnostic analytics, and statistical modeling with ad-level observational data.

  Analytics & ExperimentationTechnical Screen
• TikTokMedium·Data Scientist
  Investigating Correlation Between Ad Visits and Reports

  This question evaluates a data scientist's competency in operational analytics, including defining and aggregating metrics in SQL and applying causal reasoning to interpret correlations between ad exposures and user reports.

  Data Manipulation (SQL/Python)Technical Screen
• TikTokMedium·Data Scientist
  Maximize Distinct Purchases Within Budget Constraints

  This question evaluates understanding of selection and optimization under budget constraints, algorithmic efficiency, and the ability to implement correct logic for maximizing the number of distinct items purchased.

  Coding & AlgorithmsOnline Assessment
• TikTokMedium·Data Scientist
  Maximize products bought under budget

  This question evaluates algorithmic problem-solving skills including sorting, prefix-sum accumulation, binary search, greedy selection, careful tie-breaking for lexicographic order, and complexity analysis.

  Coding & AlgorithmsOnline Assessment
• TikTokHard·Data Scientist
  Measure Billboard Campaign Effectiveness and Engagement Quantification

  Evaluates offline marketing measurement for a billboard campaign, including how to define attributable engagement, estimate exposed population, and forecast incremental traffic, sign-ups, retention, revenue, and ROI. Strong answers use geo-lift, matched markets, or synthetic controls rather than direct attribution alone.

  Analytics & ExperimentationOnsite
• TikTokMedium·Data Scientist
  Optimize Station Sequence for Maximum Car Output in Simulation

  This question evaluates a candidate's skills in scheduling and throughput optimization, including queue management and simulation-based performance analysis within constrained buffering and station sequencing.

  Coding & AlgorithmsOnsite
• TikTokHard·Data Scientist
  Prove conversion ads value via incrementality

  This question tests your ability to design a robust incrementality experiment to measure the causal impact of advertising, accounting for selection bias and interference.

  Analytics & ExperimentationTechnical ScreenCausal InferenceA/B TestingAds Measurement
• TikTokHard·Data Scientist
  Rank factors for TikTok market entry

  This Behavioral & Leadership interview prompt for a Data Scientist evaluates cross-functional prioritization, market-entry decision-making, experimental design and measurement, commercial analytics, and regulatory risk assessment within product and growth strategy.

  Behavioral & LeadershipTechnical Screen
• TikTokHard·Data Scientist
  Reflect on a challenging project you led

  This question evaluates leadership, cross-functional influence, and applied data science competencies—focusing on ambiguity management, causal measurement, hypothesis testing, and driving product decisions.

  Behavioral & LeadershipTechnical Screen
• TikTokMedium·Data Scientist
  Resolve Stakeholder Conflicts: Actions and Outcomes Explained

  Evaluates behavioral stakeholder-conflict storytelling for data scientists delivering products or experiments. Strong answers use STAR, show empathy, structure trade-offs, drive decisions, and quantify outcomes.

  Behavioral & LeadershipOnsite
• TikTokMedium·Data Scientist
  SQL Queries and Analysis on Bad Advertisers

  This question evaluates SQL query writing, metric definition and normalization, ranking/aggregation techniques, and analytical reasoning for identifying problematic advertisers.

  Data Manipulation (SQL/Python)Technical Screen
• TikTokMedium·Data Scientist
  Select max-discount product per category

  This question evaluates proficiency in data manipulation and SQL querying—specifically use of window functions versus set-based alternatives, group-level ranking and tie-breaking, NULL-aware expressions, and numeric precision when computing discounts within the Data Manipulation (SQL/Python) domain.

  Data Manipulation (SQL/Python)Online Assessment
• TikTokHard·Data Scientist
  Test 15s to 60s video length change

  This question evaluates a data scientist's competency in experimental design, causal inference, metric definition and instrumentation, power/MDE calculations, interference and contamination handling on multi‑sided platforms, and rollout planning.

  Analytics & ExperimentationOnsite
• TikTokEasy·Data Scientist
  Test Billboard Campaign Conversion Rate Exceeds 60%

  Evaluates one-sample proportion testing for a billboard conversion rate with 65 conversions out of 100 users. Strong answers state one-sided hypotheses, compute the standard error and confidence interval, run the correct z test against 60%, and interpret why statistical evidence may be insufficient.

  Statistics & MathOnsite
• TikTokHard·Data Scientist
  Use DiD for staggered treatment adoption

  This question evaluates proficiency in causal inference for panel data, specifically difference-in-differences with staggered adoption, heterogeneous and dynamic treatment effects, event-study design, pre-trend diagnostics, cluster-robust inference, and comparison with propensity-score matching.

  Statistics & MathTechnical Screen
• TikTokEasy·Data Scientist
  When prioritize precision vs recall

  This question evaluates a data scientist's competency with binary classification metrics (precision and recall), cost-sensitive decision-making, and operating-threshold selection for productized models in the Machine Learning domain.

  Machine LearningTechnical Screen
• TikTokMedium·Data Scientist
  Write SQL for 7-day geo-localized revenue dashboard

  This question evaluates SQL skills in time-zone aware local-date aggregation, idempotent event deduplication, cohorting for new versus returning users, calculation of revenue and conversion metrics, and anomaly detection via median-based drop flags.

  Data Manipulation (SQL/Python)HR Screen