---
title: "Is Alroy's shareholder quorum subsampling really the same estimator as Chao & Jost's coverage-based rarefaction, or only a close cousin?"
type: "question"
status: "answered"
date_raised: "2026-07-12T00:00:00.000Z"
tags: ["verification","statistics-of-the-unseen","sample-coverage","paleobiology","rarefaction","source-criticism"]
answered_log: "2026-08-28 — answered by [[claim-chao-jost-2012-calls-alroys-sqs-a-different-algorithmic-technique-from-their-closed-form-estimator]], [[claim-alroy-and-chao-jost-dispute-priority-for-coverage-standardized-richness-naming]], and [[claim-alroy-distinguishes-sqs-from-rarefaction-by-fixed-coverage-not-fixed-sample-size]], written from a direct read of both named primaries (Chao & Jost 2012 via mirror; Alroy's own SQS.html). What settled it: Chao & Jost's own paper repeatedly distinguishes Alroy's SQS (a Monte Carlo resampling algorithm) from their own algorithm and their closed-form equation, and Alroy's own page draws a further, independent line (fixed coverage vs. fixed sample size) between SQS and rarefaction generally. Close cousins targeting the same quantity, not the same estimator — [[claim-paleobiology-reinvented-coverage-based-rarefaction-as-quorum-subsampling]] corrected accordingly."
---


[[claim-paleobiology-reinvented-coverage-based-rarefaction-as-quorum-subsampling]]
asserts that paleobiology's shareholder quorum subsampling (SQS) and ecology's
coverage-based rarefaction are the *same* method under two names. The
"completeness rather than size" framing is solidly Chao & Jost 2012 (Tier 1), but
the equivalence itself is Seek's synthesis, not sourced to a primary that states
the identity — hence the `[unverified-mechanism]` flag.

**What would answer it:**
- **John Alroy (2010)**, "Fair sampling of taxonomic richness and unbiased estimation
  of origination and extinction rates" (and/or Alroy 2010 *Science*, "The shifting
  balance of diversity among major marine animal groups") — read how SQS actually
  defines and hits its "quorum" of coverage.
- **Chao & Jost (2012)**, *Ecology* 93(12): 2533–2547 — read whether they identify
  SQS as an instance of, or equivalent to, coverage-based rarefaction (they discuss
  the relationship explicitly in the coverage literature).
- Determine precisely: same target quantity (Good-Turing sample coverage)? same
  estimator, or same *goal* reached by different estimators?

**Why it matters:** "same method, two field-names" is a strong convergent-reinvention
claim; "cousins targeting the same quantity" is weaker and more accurate if the
estimators differ. The note stays `seedling` until the two primaries settle which.


## Progress log

- 2026-08-28 — answered by [[claim-chao-jost-2012-calls-alroys-sqs-a-different-algorithmic-technique-from-their-closed-form-estimator]], [[claim-alroy-and-chao-jost-dispute-priority-for-coverage-standardized-richness-naming]], and [[claim-alroy-distinguishes-sqs-from-rarefaction-by-fixed-coverage-not-fixed-sample-size]], written from a direct read of both named primaries (Chao & Jost 2012 via mirror; Alroy's own SQS.html). What settled it: Chao & Jost's own paper repeatedly distinguishes Alroy's SQS (a Monte Carlo resampling algorithm) from their own algorithm and their closed-form equation, and Alroy's own page draws a further, independent line (fixed coverage vs. fixed sample size) between SQS and rarefaction generally. Close cousins targeting the same quantity, not the same estimator — [[claim-paleobiology-reinvented-coverage-based-rarefaction-as-quorum-subsampling]] corrected accordingly.