Design an A/B test for a new checkout flow
Last updated: August 16, 2025
Quick Overview
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
Robinhood
August 16, 202544
6
2,915 solved
Design an experiment to test the impact of a redesigned homepage. Include sample size calculation, metrics, and analysis plan.
Robinhood asks this during the Technical Screen to assess your experimentation skills. They want to see how you define success metrics, design controlled experiments, and interpret results with appropriate statistical rigor.
What the Interviewer Expects
- Design a rigorous experiment with proper randomization and sample size calculation
- Define primary and guardrail metrics with clear rationale
- Address novelty effects, network effects, and interference
- Segment results appropriately and identify heterogeneous treatment effects
- Propose follow-up analyses when results are ambiguous
Key Topics to Cover
How to Approach This
- Define success metrics carefully. A good metric is measurable, actionable, and aligned with business goals.
- Run experiments long enough to account for novelty effects and weekly seasonality.
- Use funnel analysis to identify where users drop off for maximum optimization impact.
- Segment results by key dimensions (platform, country, user cohort) to catch hidden patterns.
- Consider network effects and interference between treatment and control groups.
Possible Follow-up Questions
- What would you do if a stakeholder wants to end the experiment early because initial results look good?
- How would you handle seasonality in your experiment?
- How would you handle interference between treatment and control?
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Browse Analytics QuestionsSample Answer
Problem Setup
To evaluate the impact of the redesigned homepage on user engagement and conversion rates, the analytical question is: "Does the new homepage increase the percentage of users who complete a transactio...
Methodology
For this A/B test, we will use a randomized controlled trial (RCT) design. Users will be randomly assigned to either the control group (current homepage) or the treatment group (redesigned homepage). ...
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