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
Evaluate merchant partnership for high-value customers
Measure network effects and spillovers via experiments
Diagnose a sudden KPI drop and validate causes
Build dashboard; diagnose engagement–purchase gap
Measure PMF for Alexa Shopping
Explain power drivers and resolve unexpected A/B results
Design an A/B test for a Celebrate reaction
Design experiment for unconnected content in feed
Diagnose a 10% DAU drop
Analyze Change in App Metrics and Feature Impact
Diagnose Traffic Allocation in A/B Test Results
Design Metrics to Measure Inappropriate Content Severity and Prevalence
Design an A/B Test for Group Video Calls Impact
Design an Experiment to Evaluate New ML Model
Boost Engagement and Purchases in Meta Social Products
Define metrics for high-quality notifications
How would you A/B test first trade rate?
How would you analyze retail volume drop?
Decide whether to keep a negative-margin promotion
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.