Adding primary-source citations to YMYL pages: a 200-page density study

Adding primary-source citations to YMYL pages: a 200-page density study

The question: does increasing citation to authoritative primary sources — studies, guidelines, official statistics — correlate with YMYL ranking, or is it window dressing raters notice but algorithms ignore?

A health publisher's documented test: ~200 pages were revised to cite primary sources (peer-reviewed studies, official guidelines) inline, raising average citations per page from ~2 to ~9, each linked to the source. A matched control kept the original light citation. Reported result over ~6 months: heavily-cited pages improved an average of 2.0 positions; controls ~0.5.

This aligns with the QRG's expectation that high-quality YMYL content is 'consistent with well-established expert consensus' (section 3.4) and supported by reputable sources.

Counter-evidence: adding nine sourced claims per page usually means adding substantive, accurate content, so depth and accuracy are confounded with citation count itself.

Caveat: there is no evidence Google counts outbound citations as a ranking factor. The likelier reading is that pages forced to cite primary sources became more accurate and complete — and accuracy is what wins.

What we still don't know: whether citation *presence* is a signal, or whether it is merely a reliable side-effect of the rigor that produces genuinely better YMYL content. This case cannot distinguish them.