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Experimentation Methodology and Rigor Questions

Focuses on rigorous experimental methodology and advanced testing approaches needed to produce reliable, actionable results. Topics include statistical power and minimum detectable effect trade offs, multiple hypothesis correction, sequential and interim analysis, variance reduction techniques, heterogenous treatment effects, interference and network effects, bias in online experiments, two stage or multi component testing, multivariate designs, experiment velocity versus validity trade offs, and methods to measure business impact beyond proximal metrics. Senior level discussion includes designing frameworks and practices to ensure methodological rigor across teams and examples of how to balance rapid iteration with safeguards to avoid false positives.

MediumTechnical
117 practiced
You need to test three independent features simultaneously: UI change (A), recommendation ranking (B), and incentives (C). Design a factorial experiment: specify the allocation, how to test for interactions, and how to estimate marginal effects. What sample size considerations are unique to factorial designs?
MediumTechnical
65 practiced
Describe the Sample Ratio Test (SRT). How would you implement automated SRT checks in a metrics pipeline, what thresholds would you use, and what are common causes and mitigations for a sample ratio mismatch?
HardTechnical
70 practiced
You discovered many subgroup analyses showing significant effects across dozens of demographic slices. Propose a principled approach to control false discoveries across subgroups while identifying meaningful heterogeneity. Include discussion of hierarchical modeling, FDR control, and minimum subgroup size constraints.
EasyTechnical
101 practiced
Compare family-wise error rate (FWER) and false discovery rate (FDR). In a platform running thousands of concurrent A/B tests and many metric checks, when would you use Bonferroni correction versus Benjamini-Hochberg versus hierarchical Bayesian approaches for multiplicity control?
EasyTechnical
101 practiced
List the most common sources of bias in online experiments (instrumentation, randomization failure, novelty effects, etc.). For each source, give one practical detection method you would implement in an experimentation platform.

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