A/B Test Results That Tell You What to Ship
Declaring a test winner based on a raw conversion rate difference without checking sample size, segment effects, or guardrail metrics is how teams ship regressions they celebrate as wins.
The problem
- →Most teams look at the headline metric lift and declare a winner without calculating whether the result is statistically significant at their actual sample size.
- →Segment-level effects — where a variant wins for one user group and loses for another — are invisible in aggregate results and only surface when someone slices the data manually.
- →Guardrail metrics that should not move — page load time, support ticket volume, error rates — are rarely checked in the same analysis pass as the primary metric, so regressions go undetected until they show up in customer complaints.
- →Experiment data from feature flag tools like LaunchDarkly or Optimizely lives separately from product event data and business outcome data, making a complete analysis require joins across three systems.