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
Choose a precise A/B test primary metric
Decide event notification launch via experiments
Estimate Super Bowl QR-driven registrations
Design robust A/B test with interference and seasonality
Drive product decisions with causal product sense
Determine if users need a new feature
Estimate Fake Accounts Using Data Signals and Sampling
Compare Instagram and Facebook Stories Using Key Performance Metrics
Evaluate Success of 'Similar Listings' Notification Feature
Evaluate New Ad Model with A/B Testing Experiment
Design Testing Without A/B Experiments
Design Identity-Trust A/B Test
Should you roll out if NSM decreases?
How should Uber evaluate lower ETA?
How to estimate a feature’s causal impact on time spent
How to evaluate adding video ads in a game
Compute DID estimate and pretrend flag
Diagnose coffee-shop profit decline
Design a study to compare social vs game engagement
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.