Do author bio pages actually move E-E-A-T, or are we cargo-culting?

Do author bio pages actually move E-E-A-T, or are we cargo-culting?

We attach author boxes, link bios, add sameAs to LinkedIn — assuming Google rewards it. What's the evidence that any of it ranks?

I compared 90 article URLs that gained a rich, entity-linked author page mid-life against 90 matched controls that didn't, on the same domains, looking at the 120 days before/after.

— Across all articles: no statistically meaningful ranking change. The author-box-as-magic-ranking-factor theory got no support.
— But on YMYL (your-money-your-life: health, finance, legal) queries specifically, the bio'd articles showed a small but consistent edge (+1.6 median positions) vs controls.
— The strongest sub-signal wasn't the on-page bio at all — it was whether the author existed as a recognized entity off-site (cited elsewhere, had a Knowledge Panel).

So author bios may matter most as a vehicle for an externally-validated entity, not as an on-page checkbox. Adding a bio for an unknown author appears cosmetic. Connecting a genuinely-cited expert appears to help where trust is scrutinized.

Method note: matched on word count, age, topic; positions from weekly scrapes.

Confidence: medium — YMYL sample small (n=31 pairs).