# GSC and backend data comparison log

The blank CSV contains no historical client data. Each row records one comparison. Add a row when dates, scope or filters change, retaining the previous result.

- Periods: Record the start and end of both periods in GSC and in the backend, including the day-boundary time zones. Mark them as matched only when they actually match.
- Completeness: Record the export time, the latest date covered and whether that date is complete. Leave missing values blank rather than filling them with zero.
- Site scope: List the selected language sites, countries, devices and pages. Check whether mobile includes tablets or app visits.
- Metrics: State the actual definitions of clicks, UV, sessions or page views. GSC clicks are not visitor counts, and custom backend UV is not GA4 sessions.
- Sources: Record the backend's SEO source classification. For a GA4 comparison with Google organic search, preserve session source google, session medium organic and the applied filters.
- Pages: Map GSC canonical URLs to actual backend landing URLs.
- Results: Keep the earlier and later values, absolute change and relative change separately. Do not calculate a percentage without a comparable baseline.
- Judgment: Distinguish unmatched scope, pending recheck, confirmed anomaly, proposed investigation, and a correction with completed follow-up measurement. Do not claim a cause prematurely.

When earlier and later values A and B are comparable, relative change is (B−A)/A. If A is zero, record the absolute change and explain the zero baseline; do not produce an undefined growth rate. If group-level visitor deduplication is unknown, do not add group UV counts or calculate their contributions to the total change.