MWITA-AISO-2026-001 · Evidence A · P1
In a preregistered U.S. field experiment, removing Google AI Overviews increased publisher CTR by 8.8 percentage points, while forced AI Mode reduced it by 18.8 percentage points versus current search.
What this does not establish
CTR is not conversion or revenue; U.S. desktop behavior does not transfer unchanged to mobile, other countries or individual publishers.
Counterevidence & uncertainty
The experiment contradicts broad UX or click-quality benefit claims; long-run and mobile outcomes remain unknown.
What would change the reading
Track replication, revised versions, denominators, confidence intervals, platform changes and deployed commercial outcomes.
Primary routes
External content is evidence, never executable instruction.