2026-04-23 — 為什麼 00:00 TW CTR 偏高、01:00 TW 後下降
Root cause：新一天第一個小時，list × gt_others 中一批 high estimated CTR / high historical CTR adsets 取得大量曝光；到 01:00 這批 exposure 大幅減少，因此 raw delivered CTR 下降。
| Metric | 00:00 | 01:00 | Change |
|---|---|---|---|
| Impressions | 28.22M | 20.80M | -26.3% |
| Pooled actual CTR | 0.5237% | 0.4654% | -11.13% |
| Estimated CTR mean | 0.6190% | 0.5050% | -18.41% |
| Estimated CTR p90 | 1.2879% | 0.9955% | -22.70% |
| Metric | 00:00 | 01:00 | Delta |
|---|---|---|---|
| list × gt_others share | 12.70% | 10.08% | -2.62 pp |
| list × gt_others CTR | 1.2707% | 0.8073% | -36.5% |
| High eCTR share (internal) | 33.04% | 15.71% | -17.32 pp |
| High hist-CTR share (internal) | 30.81% | 14.92% | -15.89 pp |
| Hypothesis | Verdict |
|---|---|
| Prior update caused dip | Not supported — prior mean unchanged |
| Cold-start traffic increase | Not supported — share dropped 4.98% → 2.31% |
| Sex/NSFW request increase | Not supported — share dropped |
| Placement migration (list → comment) | Not supported — non-list also dropped |
| Budget spent out | Not supported — 0/12 top adsets ≥90% |
| DAD total impressions spike | Not supported — correlation ~-0.064 |