A/B Testing Interview Questions
A/B testing questions are central to data science and product analytics interviews at companies like Meta, Google, Netflix, and Airbnb.
Expect questions on experiment design, randomization units, sample size calculation, multiple comparisons, and metric selection.
Interviewers evaluate your statistical rigor, practical judgment, and ability to communicate experiment results.
Common A/B testing interview patterns
- Designing an experiment for a product change
- Calculating sample size and experiment duration
- Choosing between one-sided and two-sided tests
- Handling multiple comparisons and peeking
- Interpreting results with novelty or primacy effects
- Network effects and interference between test groups
A/B testing interview questions
Design and assess video-pin increase experiment
Diagnose conversion-rate time series and CTA swap
Identify Issues and Redesign Customer-Conversion Chart
Analyze Trends to Diagnose Decline in Job Applications
Evaluate marketplace interventions
Design pricing and multivariate button experiments
Decide to ship a signup experiment
Interpret A/B results for video-pin increase
Define success metrics for a social feed
Diagnose Decline in Delivery Success: Data, Hypotheses, Tests
Evaluate Auto-Reply Feature Success with Metrics and Experiments
Analyze Revenue Shifts to Identify Cannibalization Effects
Define and apply Gmail user segments
Optimize Credit-Card Strategy: Pricing, Limits, and Target Segments
Maximize credit card portfolio profit
Measure driver experience quantitatively
Evaluate AI-assisted ad creation
Design an A/B test with guardrails and SRM checks
Diagnose Delivery Delays: Key Metrics and Experiment Design
Common mistakes in A/B testing interviews
- Not specifying the randomization unit (user vs session vs page)
- Peeking at results before reaching the required sample size
- Ignoring practical significance when statistical significance is achieved
- Not considering guardrail metrics
- Failing to account for novelty effects in short experiments
How A/B testing questions are evaluated
Structure your experiment design: hypothesis, metrics, unit, sample size, duration.
Discuss what could go wrong and how you would detect it.
Show ability to make a recommendation even when results are ambiguous.
Related analytics concepts
A/B Testing Interview FAQs
How do you determine the sample size for an A/B test?
Use a power analysis with inputs: baseline metric, minimum detectable effect (MDE), significance level (alpha, usually 0.05), and power (usually 0.80). Larger effects need fewer samples. For small MDE on rare events, you may need millions of users.
What is the difference between statistical and practical significance?
Statistical significance means the observed difference is unlikely due to chance (p-value < alpha). Practical significance means the effect is large enough to matter for the business. A statistically significant 0.01% lift may not be worth the engineering cost to ship.