Decisions 34-37 (sharp disease null, threat strengths, NCE adjustment, sorting) applied to the analysis plan

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

docs/decisions.md

@@ -64,3 +64,13 @@ Each decision is listed with the date and the reason for it. Settled decisions a
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 | 32 | **Three negative controls.** **NCO-1:** hip fracture / pneumonia admission. Shares the latent patient frailty, severity and smoking, so it targets factor 5. **NCO-2:** varicose vein ablation by the same physician. Shares physician procedural style, so it targets factors 2–3. **NCE:** early low-value procedure (e.g. vein ablation) within 6 months, which shares both. All three are generated only from latent traits and never depend on PVI, so their true effect is exactly 0. They go through the same method × physician-variant pipeline as MALE. | Negative controls are the practical bias check available in real claims. CCW and landmark condition on survival, so the controls also need testing under each design. |
 | 33 | **Main text (Figure 3 / Table 3):** how accurately the negative controls detect bias. A control is "flagged" if its CI excludes 0. Bias in the MALE risk difference counts if |bias| > 1 percentage point. Report sensitivity and specificity, plus how much bias can sit behind a clean negative control. **Supplement:** each control's own false-positive rate. | Answers a new, practical question: what does a clean negative control actually tell a surgeon? |
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+## Round 7: issues raised by drafting the plan (2026-10-27)
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+| # | Decision | Why |
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+| 34 | **Null scenario = sharp disease null** (Δ = κ = 0). The headline false-alarm rate is reported for the disease composite (CLTI or major amputation), whose true effect is exactly 0. MALE in the null world is reported as "harm" that comes from the outcome definition alone. | Repeat revascularization can only happen after an index PVI, so MALE cannot be exactly null. Showing that is a teaching point. |
+| 35 | **Strength of each threat:** use an empirical anchor where one exists (style spread from Hicks 2020; deferred PVI from Sorber late-PVI rates; the early-PVI rate). Where none exists (skill, coding), set the threat so that on its own it moves the naive or landmark estimate by about 2–4 pp in the harm scenario. | Credible to surgeons while keeping each threat's effect visible. |
+| 36 | **The NCE analysis is adjusted for early-PVI status.** The unadjusted version goes in the supplement. | Otherwise NCE ← style → PVI → MALE flags a real effect of PVI. |
+| 37 | **Patient–physician sorting is not in the main grid.** It becomes one sensitivity world if time allows. | Scope. |
+| — | **Fact (not a decision):** interim calibration target for all-cause mortality is about 35% at 5 years (Sigvant 2018 *EJVES*, PMID 29478910: 10-year mortality in IC 63%). To be replaced by the 5-year mortality in the authors' own Medicare cohort. | No published 5-year all-cause figure for Medicare claudicants was found. |