Evaluative analysis for cross-system metric discrepancies — "why don't these two tools agree," GA4 vs. the ad platform, analytics vs. the backend, BI vs. finance, "which number is right." Use this skill whenever two or more systems report different values for nominally the same metric and someone wants the difference explained, resolved, or adjudicated — even if they frame it as "fix the tracking" or "make these match." Do NOT use for a change over time within a single system (use root-cause-analysis) or for validating a single analysis's methodology.
