Core metrics
When comparing aggregate CTR, divide total clicks by total impressions. Averaging row-level CTR values gives each row equal weight and can misrepresent the result.
Google explains the metrics in its Search Console performance report guide.
Dates and freshness
Search Console date boundaries use Pacific time. Use explicit inclusive start and end dates when reproducibility matters. For a routine complete-period review, choose a range ending at least three days ago and check the response’s freshness warnings. This is a conservative workflow convention, not a guarantee that every source is complete on that date. Advanced analytics acceptsdata_state: "final" or "all". Use final data for completed-period comparisons. If you include preliminary data, label it.