Speed-ups (shared PVI fit, clones once, case-control sampled deferred model); final scale 200 reps extending the draft (D51)

Co-Authored-By: Claude Opus 5.5 <[email protected]>

docs/decisions.md

@@ -102,3 +102,4 @@ Each decision is listed with the date and the reason for it. Settled decisions a
 | 48 | **The PVI model is fitted separately inside the window (month indicators) and in the deferred period (spline in month).** | A pooled model misspecified the window probabilities that the CCW and sequential weights depend on. |
 | 49 | **V2 is the V1 fit with a physician-cluster-robust SE.** Under V4, physicians without an estimable fixed effect in a phase get probability 0, and the V4 population is restricted to physicians with variation in early PVI. | Same point estimate by construction (D15). |
 | 50 | **Validation (W0, harm, 40 replicates of 50,000):** CCW A−B1 is +5.12 vs a truth of +5.11 on the disease composite (z = 0.0); sequential ITT is +5.83 vs +5.71 (z = 0.6); MALE and NCO-1 have |z| ≤ 0.7. The model SE is 0–20% below the empirical SE for CCW, so the bootstrap check in D28 still needs doing. | Plan §15 validation (a). |
+| 51 | **Speed and scale.** The PVI model is fitted once per replicate and variant, and shared by CCW and the sequential trials. CCW clones and weights are built once for all outcomes. The deferred-period PVI model uses every PVI plus a fixed 10% sample of the other person-months, with offset log(10). On W0 validation the estimates are identical to 4 decimals. The main designs take about 39 s per replicate instead of about 130 s. **Scale:** n = 50,000 stays. Draft is 100 replicates; final is 200 replicates (replacing 500 in D29), and the final run extends the draft's replicates 1–100. Total about 12 hours on 11 cores. | User asked for a faster, smaller run. The sample size is not reduced, because CCW's strategy A already depends on about 250 patients treated in month 5 at n = 50,000. With 200 replicates, MCSE of bias ≈ empirical SE / 14 (CCW about 0.2 pp) and MCSE of coverage ≈ 1.5%. |