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 experiment with network and novelty effects
Select interest thresholds under skewness and cost
Design a flu-shot A/B/n campaign experiment
Prove new allocation outperforms manual baseline
Causally measure traffic reduction effectiveness
Design and analyze an ads ranking experiment
Challenge and validate assumptions
Design and analyze a card signup A/B test
Allocate Support Cost and Diagnose Decline
How to analyze Simpson's paradox
Determine User Demand for New Video-Calling Feature
Evaluate Instagram Shopping Tab Success with Key Metrics
Analyze Comment Distribution Using Statistical Metrics and Tests
Convince Leadership to Launch Group Chat Feature
Optimize Experiment Thresholds for Impactful Feature Launches
Evaluate Success of B2C Chat App with Key Metrics
Analyze DoorDash marketplace product decisions
Design Identity & Trust Experiment
Evaluate business value of lower ETA
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.