Conciseness

Nearly every line carries a rule, a number, or a named benchmark ('about 8% of Microsoft experiments had SRM', 'fixed horizon of two weeks', '5% per quarter'); there is no padding explaining what A/B testing is, which Claude already knows. Minor instances could be trimmed — the dense per-guest attributions and the six inlined quote receipts — fitting 'efficient; minor instances of over-explanation that could be trimmed'.

Actionability

Fully executable guidance for an instruction-only skill: a copy-paste-ready deliverable template with fill-in blanks, a decision table mapping each result class to a default call, a 1/3/5 grading rubric with concrete anchors, and specific thresholds (200,000 users, 26% false-positive risk, 3/6/9/12-month re-reads). Concrete instruction covers the common cases end to end.

Workflow Clarity

The sequence is explicit (Diagnose with at most 4 questions → Pick the play via routing table → Run the selected play → deliverable → grade), with validation checkpoints as first-class steps: the Trust Checklist is explicitly run 'before anyone reads the lift', SRM failures are 'Invalid; fix and rerun', and SRM debugging steps name causes (bots, pipeline filters, side-campaign traffic). Red flags act as an error checklist.

Progressive Disclosure

The 'Go deeper' section cleanly signals two one-level-deep references that both exist and expand the body rather than duplicating it, and cross-links related skills. Minor gap: six verbatim quote receipts are inlined in the body while a separate references/quotes.md already holds the full verified quote set, so a little content that belongs in the bundle file is inline.

Specificity

The description lists multiple concrete, comprehensive actions ('Designs, sanity-checks and reads out product experiments (A/B tests, holdouts, pre/post, geo and incrementality tests) and produces an experiment brief plus a readout with a ship / hold / replicate call') with enumerations of test types and deliverables. This is a 5 on capability detail, reduced by 1 per the rubric's voice penalty because the trigger clause uses second person ('Use when you ask...') instead of third person.

Completeness

Clearly answers both what (designs/sanity-checks/reads out experiments; produces brief and readout with a ship/hold/replicate call) and when, with an explicit 'Use when...' clause listing concrete trigger phrases. This mirrors the anchor-5 example structure exactly.

Trigger Term Quality

Comprehensive coverage of natural phrases users would actually say: 'should we A/B test this', 'how long should the test run', 'is this result real', 'our win rate is low', plus jargon synonyms and abbreviations ('sample size', 'stat sig', 'SRM', 'holdout'). Matches the anchor-5 example's breadth including synonyms.

Distinctiveness Conflict Risk

The experimentation niche is clear with distinctive triggers (SRM, stat sig, holdout, sample size) unlikely to fire for unrelated skills. However, gate-type phrases like 'should we A/B test this' overlap with closely related validation/idea-testing skills, fitting 'mostly distinct; minor overlap risk' rather than the minimal-conflict anchor 5.