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Data Scientist Interview Questions
Practice 9403 coding, system design and machine learning questions from 546 companies, sorted by role, topic and interview round. Every question has step-by-step hints, a code runner that supports 8 languages and an AI mentor; members also get the full solution walkthrough.
- 9403
- Questions
- 546
- Companies
- 11
- Topics
- 8
- Languages
Showing 1–30 of 1971 results
- AdiaEasyData ScientistCalculate Playback Counts per Stream
This question tests the ability to perform relational database joins and use aggregate functions (COUNT) with grouping to summarize event-level data.
Software Engineering FundamentalsTechnical ScreenSQLJoinsAggregation - AdiaEasyData ScientistCompute Score Difference in Reversing Array Game
This question tests the ability to manage state changes while iterating through an array based on index-dependent rules, specifically involving conditional array modifications.
Coding & AlgorithmsTechnical ScreenArraysSimulationDeque - AdobeEasyData ScientistDescribe Your Background and Alignment with This Role
This interview question evaluates behavioral evidence, ownership, communication, trade-offs, and measurable outcomes in a realistic interview setting. A strong answer for Describe Your Background and Alignment with This Role states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Behavioral & LeadershipOnsite - AdobeMediumData ScientistDesign Metrics Framework for Adobe Express Performance Evaluation
This interview question evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer for Design Metrics Framework for Adobe Express Performance Evaluation states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationOnsite - AdobeMediumData ScientistSolve SQL and Python Data Manipulation Tasks
This question evaluates proficiency in SQL event-log aggregation and basic Python data-structure transformations, assessing competencies such as counting distinct users, identifying frequent event types, and performing dictionary/list/string manipulations.
Data Manipulation (SQL/Python)Onsite - AdobeEasyData ScientistUnderstand P-Value's Role in Product Decision-Making
This interview question evaluates statistical assumptions, formulas, estimation strategy, uncertainty, edge cases, and interpretation in a realistic interview setting. A strong answer for Understand P-Value's Role in Product Decision-Making states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Statistics & MathOnsite - AffirmMediumData ScientistAnalyze Loan Payments Using Pandas for Key Insights
This question evaluates data manipulation and aggregation skills using pandas, focusing on computing per-loan payment totals, payment success rates, and a repayment-status flag. It is commonly asked to assess applied data wrangling and numeric summarization abilities in the Data Manipulation (SQL/Python) domain, testing practical application rather than purely conceptual understanding.
Data Manipulation (SQL/Python)Technical Screen - AffirmEasyData ScientistCalculate Profit of 4-Month Loan at 30% APR
This interview question evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer for Calculate Profit of 4-Month Loan at 30% APR states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - AffirmMediumData ScientistDiagnose Sudden Drop in Credit-Card Approval Rate
This interview question evaluates metric design, causal reasoning, experiment setup, diagnostics, SQL/statistical checks, and recommendations in a realistic interview setting. A strong answer for Diagnose Sudden Drop in Credit-Card Approval Rate states assumptions, handles edge cases, explains trade-offs, and shows how to validate the result clearly.
Analytics & ExperimentationTechnical Screen - AirbnbMediumData ScientistAggregate User Activity, Fit Regression, Interpret Coefficients
This question evaluates skills in relational data aggregation and feature engineering using SQL alongside fitting and interpreting regression models in Python, targeting competencies in transforming event-level user metrics into a modeling dataset and interpreting coefficient estimates.
Data Manipulation (SQL/Python)Technical Screen - AirbnbMediumData ScientistBuild and evaluate an order prediction model
This question tests the ability to design a robust end-to-end machine learning pipeline for binary classification, focusing on preventing temporal data leakage, managing class imbalance, and aligning model thresholds with business objectives.
Machine LearningTechnical ScreenClassificationTemporal LeakageModel Evaluation - AirbnbMediumData ScientistBuild panel in SQL; run causal regression
This question evaluates proficiency in SQL-based panel data construction, time-series aggregation and rolling-window metrics together with applied causal inference in Python, including two-way fixed-effects difference-in-differences, clustered standard errors, lead tests, and count-model re-specification; it targets Data Manipulation (SQL/Python) skills relevant for Data Scientist roles. It is commonly asked because it combines practical implementation and conceptual understanding—testing temporal joins, treatment timing, avoidance of lookahead/immortal-time biases and late-adopter issues, interpretation of interaction coefficients and confidence intervals, and the ability to reason about identification and model choice.
Data Manipulation (SQL/Python)Technical Screen - AirbnbMediumData ScientistCompute C/T metrics from bookings and visits
This question evaluates time-window attribution, visit deduplication, control vs treatment metric computation, aggregation of conversions and revenue, and statistical interval estimation (Wilson CIs), testing practical data manipulation skills with SQL or Python in the Data Manipulation (SQL/Python) domain.
Data Manipulation (SQL/Python)Technical Screen - AirbnbMediumData ScientistCompute browsing metrics in Python from logs
This question evaluates a candidate's ability to perform event-level data manipulation and analytics in Python and SQL, covering sessionization, time-zone–consistent timestamp handling, deduplication, funnel construction, segment-level aggregation, conversion-rate computation, and statistical confidence intervals such as the Wilson CI.
Data Manipulation (SQL/Python)Technical Screen - AirbnbMediumData ScientistDefine Success Metrics and Experiment Plan for Product Development
Evaluates product-planning metrics and experiment design for a two-sided marketplace booking funnel. Strong answers define a primary booking metric, diagnostic and guardrail metrics, randomization unit, sample size, marketplace spillovers, and launch criteria before development.
Analytics & ExperimentationTechnical Screen - AirbnbMediumData ScientistDescribe How You Use SQL in Data Science Work
This question assesses a candidate's ability to articulate their technical workflow in SQL, focusing on data extraction strategies, quality assurance, and how technical analysis translates into business impact.
Data Manipulation (SQL/Python)HR ScreenSQLData ScienceAnalytics - AirbnbMediumData ScientistDesign a network-aware Wi‑Fi badge experiment
This question evaluates a data scientist's proficiency in experimental design, causal inference under interference (including SUTVA risks), metric specification, power and sample‑size computation, analysis planning, and translating treatment effects into financial decision rules.
Analytics & ExperimentationTechnical Screen - AirbnbHardData ScientistDesign an A/B test with causal inference
This question evaluates skills in experimental design, causal inference, and applied statistics — including estimand selection, sample-size calculation under clustering, integrity monitoring, handling noncompliance and contamination, sequential monitoring, and two-proportion inference — within the Analytics & Experimentation domain for a Data Scientist role. It is commonly asked because interviewers need to assess the ability to design and analyze robust A/B tests under real-world constraints; the prompt requires both conceptual understanding of causal assumptions and practical application of power calculations, diagnostics, and monitoring procedures.
Analytics & ExperimentationTechnical Screen - AirbnbMediumData ScientistDesign and Analyze Airbnb Locker Experiment
This question evaluates a candidate's skills in experimental design and causal inference for marketplace features, including selecting the appropriate randomization unit, defining eligibility and treatment/control arms, and choosing primary, secondary, and guardrail metrics.
Analytics & ExperimentationTechnical Screen - AirbnbHardData ScientistDesign and assess an A/B test
This problem tests your ability to design a statistically sound A/B test for a marketplace platform, including metric selection, power analysis considerations, and handling potential interference effects.
Analytics & ExperimentationOnsiteA/B TestingExperimental DesignMetrics - AirbnbHardData ScientistDesign robust primary and guardrail metrics
This question evaluates proficiency in experiment metric design, guardrail definition, data quality diagnostics, and statistical analysis for A/B testing, including power calculations and sequential monitoring, within the Analytics & Experimentation domain.
Analytics & ExperimentationTechnical Screen - AirbnbHardData ScientistEstimate Causal Impact Using Synthetic Control Methods
Evaluates causal impact estimation after a full product rollout with no holdout. Strong answers use interrupted time series, synthetic control, Bayesian structural time series, exposure variation, and placebo tests to build and validate a credible counterfactual.
Analytics & ExperimentationTechnical Screen - AirbnbHardData ScientistEstimate impact of global launch without holdout
This question evaluates a candidate's competence in causal inference, observational study design, and statistical uncertainty quantification for product analytics, specifically estimating lift after a global launch without a holdout while addressing confounding, interference, and operational data-quality issues.
Analytics & ExperimentationTechnical Screen - AirbnbMediumData ScientistInfluence Decisions Without Direct Authority: Strategies and Outcomes
Evaluates behavioral storytelling for influencing decisions without direct authority. Strong answers use STAR, map stakeholders, build alignment with shared goals and evidence, handle objections, quantify outcomes, and show how the candidate drove a decision without formal power.
Behavioral & LeadershipTechnical Screen - AirbnbHardData ScientistLead cross-functional decision without RCT evidence
This question evaluates a data scientist's cross-functional decision-making, experimental-design reasoning without a holdout, metric definition, and stakeholder-influence skills within a product analytics context.
Behavioral & LeadershipTechnical Screen - AirbnbMediumData ScientistPresent and Defend a Product Experiment You Designed
Tests a candidate's ability to communicate and defend an end-to-end product A/B test with technical depth, covering hypothesis formulation, experimental design, metric trade-offs, and post-experiment business decisions.
Behavioral & LeadershipHR ScreenA/B TestingExperimentationBehavioral - AirbnbMediumData ScientistTest conversion difference and adjust for clustering
This question evaluates proficiency in statistical inference for A/B testing—estimating and comparing conversion proportions, conducting two-sided hypothesis tests, adjusting for day-level clustering using ICC and design-effect corrections, and performing power and sample-size calculations; it belongs to the Statistics & Math domain for a Data Scientist role and combines conceptual understanding with practical application. It is commonly asked to assess an interviewee's ability to interpret conversion uplift under realistic experimental constraints, account for intra-cluster correlation when estimating effective sample sizes and uncertainty, and reason about experiment duration and robustness checks.
Statistics & MathTechnical Screen - AirbnbMediumData ScientistWalk Through an Experiment From Design to Decision
Walk through an end-to-end A/B test for an online marketplace feature, covering metric definition, randomization design, SRM diagnosis, and making a launch decision with conflicting trade-offs.
Analytics & ExperimentationHR ScreenExperimentationA/B TestingProduct Analytics - AirtableEasyData ScientistDiagnose metric anomalies and evaluate new algorithm
This question tests your ability to systematically investigate a sudden drop in a key product metric and design a robust A/B test to evaluate the impact of a new recommendation algorithm.
Analytics & ExperimentationTechnical ScreenA/B TestingProduct AnalyticsRoot Cause Analysis - AirwallexMediumData ScientistCompute Moderation View Metrics
An Airwallex Data Scientist onsite SQL question on content-moderation analytics. You write three queries over a per-day view table and a one-to-many post/violation-type policy-score table: distinct posts with 10+ views in the last 7 days, Nudity view prevalence over the last 30 days, and a monthly violation-type distribution. The core challenge is windowed aggregation plus avoiding view double-counting across violation types.
Data Manipulation (SQL/Python)Onsite