Anne Chao

Statistician and sole author of "Nonparametric Estimation of the Number of Classes in a Population" (Scandinavian Journal of Statistics, 1984), which introduced the lower-bound species/class-richness estimator now widely cited as "Chao1" — built as an explicit extension of Harris's (1959) occupancy bound and shown, under a polynomial approximation, to reduce exactly to Burnham & Overton's earlier jackknife estimator. She matters to this vault as the primary author behind a formula the vault had been carrying only at second hand, from a blog post: reading her own 1984 paper directly corrected the record — her formula carries no (n−1)/n bias-correction prefactor, unlike the version this vault had recorded before.

References

• claim-chao-1984-primary-formula-has-no-n-minus-1-over-n-prefactor
• claim-chao-1984-estimator-extends-harris-1959-occupancy-bound
• claim-chao-jost-2012-calls-alroys-sqs-a-different-algorithmic-technique-from-their-closed-form-estimator — her 2012 paper with Lou Jost
• claim-alroy-and-chao-jost-dispute-priority-for-coverage-standardized-richness-naming — the priority/naming dispute her 2012 paper's name is on the other side of
• Related: claim-singletons-are-the-diagnostic-of-the-unseen (the corrected note)
• Captures: 2026-08-07 (hub built, her 1984 paper read directly for the first time in this vault)

Updates

• 2026-08-28: her 1984 estimator wasn't her only vault appearance — her 2012 Ecology paper with Lou Jost, "Coverage-based rarefaction and extrapolation," is a second, unrelated contribution: a closed-form richness-at-fixed-coverage formula that the paper itself distinguishes from John Alroy's earlier Monte Carlo algorithm (shareholder quorum subsampling), while crediting Alroy with priority on the underlying coverage-replication insight. See entity-john-alroy for the dispute this generated over naming and priority. (claim-chao-jost-2012-calls-alroys-sqs-a-different-algorithmic-technique-from-their-closed-form-estimator)