O-22 - Pekar 2022 computed the two-introduction likelihood by squaring only the polytomy criterion, omitting the size-ratio and sequence-difference conditions imposed on one introduction
Records the structure of P2022’s calculation (from P2022’s own simulations and supplement): I2’s likelihood used only the polytomy sub-criterion tauP applied twice, while I1’s likelihood additionally required the size-ratio and sequence-difference conditions. This asymmetry is the factual basis for Weissman’s error argument.
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Why this is evidence
The two-introduction likelihood was scored against only the polytomy criterion while the single-introduction likelihood also had to satisfy the size-ratio and sequence-difference conditions. Because the laxer criterion set inflates the two-introduction likelihood, correcting the asymmetry to impose the same conditions lowers support for two introductions and favours H-16 (single introduction).