Average position can drop while an SEO change is working. How I check before/after instead

A pattern I see a lot when founders judge an SEO change (new title, rewritten page, a few links): they open Search Console, see the average position got worse, and roll the change back. Often the page was doing better.

Average position is an average over every query the page shows up for. When a page starts appearing for new, longer queries at position 30 or 40, those pull the average down, even though impressions and clicks are going up. So a falling average can mean Google is testing the page for more searches, not that it lost ground.

What I check instead, per page, not per site:

1. Compare two windows of the same length, both ending on the same weekday, and skip the week the change went live.
2. Look at impressions and clicks first. They answer "is the page being shown and chosen more".
3. Then open the Queries tab and check position only for the 3 to 5 queries that matter, one by one.
4. Check the same weeks last year, so a seasonal bump doesn't get credited to the change.
5. Give it at least 3 to 4 weeks before deciding anything.

This is also why our reports at PromoPilot show was and became per page, with impressions and clicks next to position, instead of one site-wide number.

What do you look at first when you decide whether an SEO change worked?