Under a single point-source emergence at location X, the earliest cases of each introduced lineage should cluster around X. Observing that both lineage A (earliest cases) and lineage B (n=11) independently cluster near the same market is therefore expected if X = Huanan market, and requires a coincidence otherwise. A lab-origin scenario would instead predict the earliest cases to centre near the implicated institute (several km away across the river), not the market. Validity caveats (for scoring): the lineage-confirmed subsets are very small (n=2, n=11), the p-values are near threshold (0.034, 0.017), the case set is ascertainment-limited, and a 2024 erratum revised the null-model generation, all of which the Stoyan-Chiu and Weissman critiques press on.
Validity verdict
status: approved; reason_if_not_false: checked. Premises (granted, not tested here): two genuinely independent introductions (lineage A and lineage B) whose earliest cases each cluster near the market. Load-bearing step: under point-source emergence at X the earliest cases of each lineage cluster at X, so both lineages centering on the market is expected iff X = market and requires a coincidence otherwise, disfavouring a distant single origin including a lab. Probed the main undercutting defeater — that the market is a shared amplification venue rather than the emergence locus (the A-41/A-42 theme), so both lineages could center on it while emerging elsewhere. This defeater does not survive for the two-independent-introductions case: it requires a distant source to seed the market twice independently, which is itself improbable, whereas two independent zoonotic spillovers at an active wildlife market are natural; hence the step holds conditional on the independence premise. Note the listed caveats (small n, near-threshold p, ascertainment, erratum) bear on premise truth/strength and are priced at step 8, not here. The conclusion is already correctly hedged (“points to”/“disfavors”), so no correction needed. Approved, checked.