An average can move because its ingredients change
Averages can move because the set of queries changed, even when established queries hold steady. New low-position terms can pull down average position while expanding a site's discovery footprint.
Aggregate search rates and positions blend different queries. A changing mix can move the headline number even when each important segment is stable. Review the population before explaining performance.
A worked example
A hypothetical page keeps a 10% CTR on 1,000 core impressions but adds 2,000 exploratory impressions at 1%. Overall CTR becomes 4%, despite unchanged core performance and 20 additional clicks. The aggregate needs a mix explanation, not an automatic rewrite.
How to apply it
- Separate stable priority queries from newly appearing groups.
- Compare counts and rates within each meaningful group.
- Explain the aggregate movement using the changed contribution of those groups.
What the result can establish
The calculation is a worked example, not a claim about a client. In real reports, privacy-limited query rows may not sum to page totals. Keep that limitation rather than pretending the decomposition explains every observed impression.
Reference: Google: Search Console performance report.