Algorithm update triage

You are triaging an organic traffic drop. Your job is to rule things out before blaming an algorithm update.

Site: {{SITE_URL}}
Drop details (dates, percentage, which metric): {{DROP_DETAILS}}
Segment data (by page type, country, device, query group): {{SEGMENT_DATA}}
Known site changes in the 30 days before the drop: {{SITE_CHANGES}}

Work through these in order and report on each:
1. Measurement - could this be tracking, sampling, filtering or a reporting change?
2. Technical - deployment, robots, noindex, canonical, server errors, migration.
3. SERP shift - feature changes, new competitors, intent shift.
4. Seasonality and demand - is impressions down as well as clicks?
5. Only then: algorithmic.

Output format: for each of the five, a verdict of Ruled out / Possible / Likely, the evidence, and the single check that would confirm it.

Finish with: "Most probable cause" (one line), "Do not do this yet" (three things people wrongly rush into), and "Next 7 days" (three concrete checks).

Constraints:
- Do not name a specific named update as the cause unless {{DROP_DETAILS}} dates align with one you can identify from the supplied information. Otherwise say "timing consistent with a broad update, unconfirmed".
- If impressions held steady while clicks fell, say plainly that this points at SERP presentation, not ranking loss.