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 DoorDash Marketplace Experiments
Analyze a geo rollout and interpret charts
Evaluate New Model's Impact on Rider and Driver Experience
Improve biker delivery with metrics and levers
Define Ultra success metrics and detect suspicious transactions
Design an Unbiased Upgrade Experiment
Analyze A/B test with revenue–cost tradeoffs
Design an experiment to launch fractional shares
Diagnose Revenue Decline: Key Analyses and Metrics
Design a Top Dasher experiment with interference
How would you test product changes?
Design a Causal Upgrade Experiment
How do you diagnose a ratio metric change
How would you measure App Store launch success?
Diagnose 10–11% usage drop across geos
Measure Ads Manager effectiveness end-to-end
Evaluate Core Metrics for New Product Feature Launch
Calculate Profit-Maximizing Price and Validate with Additional Data
Estimate Successful Sign-ups from Super Bowl QR Code Ad
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.