lab-notes

Deploy quality: why two Lighthouse runs disagree (2026)

Two Lighthouse runs on the same deployed AI-builder output rarely return the same score. This note documents the variance phenomenon, names its seven sources from Google's own documentation, and publishes the median-of-five protocol a hands-on deploy-quality harness would have to meet. Corrected August 21, 2026: the June 2026 result table it accompanied has been withdrawn, and the account of how that table was produced is withdrawn with it.