Hey all, I’m running a PDP experiment on our apparel site where the treatment is inside our sizing tool on the PDP, but the experiment is scoped to all product pages. Only ~25% of visitors use the sizing tool flow we’re testing so I only want to include those users who used the sizing tool for the analysis. To narrow the dataset, I’ve tried two approaches: 1. Activation metric: using a GA4 event (

start_sizing_tool

) as the activation metric. 2. Segment: creating a segment that includes only users who have triggered

start_sizing_tool

. Both these approaches use the same GA4 event In theory these should produce similar experiment populations, but in practice they’re very different - the activation metric looks accurate when I compare to GA4 over the same period of the test but the segment cuts my experiment population by more than half. Why does activation vs. segment produce such different populations, and which is the correct approach for an experiment where only sizing-tool users should be evaluated?