When AdSense RPM drops, which denominator do you check first?

Asks whether publishers check traffic mix, coverage, matched requests, or page changes before blaming a niche.

When AdSense RPM drops, I try to separate the revenue change from the denominator change. The first checks are traffic source, country mix, coverage, ad impressions, and whether a template or consent change happened. A niche may be weaker, but the report should prove that before the creator changes the whole content plan. Which denominator do you check first when RPM moves suddenly?