OUHUDSearch Intelligence
Knowledge

What is evidenced — and what is not

In this field a lot is claimed and little is measured. These pages only carry statements for which a survey exists — with source, sample size and date. Where we know nothing, that is stated too.

How we handle evidence

Not every figure carries the same weight. A controlled comparison says more than a correlation, and an agency study more than a claim without data. That is why we note for every figure where it comes from and how sound it is — even when that weakens our own point.

For some questions there simply is no sound answer. Google AI Overviews, for instance, cannot be measured reproducibly from the outside. That then stands as a gap, not as an estimate.