ad-test-designer

# Ad Test Designer Designs paid-ad creative/landing A/B/n and incrementality tests and reads them out: hypothesis, variant matrix, sample-size/duration/power plan, effect size, uncertainty, practical-effect status, and guardrail state. This skill owns **experiment design + statistical interpretation**. It may apply an owner-approved, precommitted action rule, but it never treats a p-value or helper output as an automatic business decision. It does not produce variants (`ad-creative-builder`), read back one already-shipped change (`paid-measurement-loop`), or do cross-channel reporting (`performance-analyzer`). ## Quick Start ```text Design an A/B test for two landing-page hero variants. Baseline CVR is 3%, I want to detect a 15% lift. Goal is DR. ``` ```text I have 4 RSA creative variants to test on a prospecting set. Build the variant matrix, sample size, and run duration. ``` ```text Here's my finished test results CSV (variant, sessions, conversions). Is the winner significant — promote or kill? ``` ## Skill Contract - **Expected output**: a test design (hypothesis, variant matrix, primary/secondary/guardrail metrics, sample-size + duration + power plan) **and/or** a read-out (effect estimate, interval, statistical flag, practical-effect flag, guardrails, and either an owner-governed recommendation or `decision: UNDECIDED`). - **Reads**: what the user wants to test, the ROAS profile (`direct-response|prospecting|incremental-profit`), baseline CVR/CTR and traffic volum...