Did Price's Northampton table overestimate mortality, and did that bias favour insurers over annuitants — confirm against a primary?

actuarial-historyinsurancemortality-tableshistorical-demographysource-verification

The claim that Richard Price's Northampton mortality table systematically overestimated mortality — "good for the insurance business, and adverse for those purchasing annuities" — currently rests on a Tier 3–4 secondary summary and carries an [unverified-quant/mechanism] flag (see claim-price-northampton-table-overestimated-mortality-favouring-insurers). A directional-bias claim with a stated winner and loser is exactly the kind of quantitative-mechanism assertion the sourcing floor requires a Tier 1–2 source for.

What to read. (1) Price's Observations on Reversionary Payments (1771) and the Northampton table itself, to see how the survivorship figures were constructed (the table is often said to have failed to account for in-migration inflating apparent deaths, or for baptism-vs-birth undercounts). (2) A methodological history of the table — e.g. actuarial histories of the Equitable and the Northampton table's later replacement — that quantifies the direction and magnitude of the bias. (3) Confirm the economic incidence: an overestimate of mortality makes life-assurance premiums conservatively high (favouring the insurer) and annuity prices too low relative to true longevity (adverse to the annuity seller, or the buyer, depending on framing) — the capture's "adverse for those purchasing annuities" phrasing should be checked for direction.

Why it matters. This connects to the vault's demographic source-criticism thread — mortality data built for one purpose and read too straight (cf. claim-osteological-paradox-skeletal-statistics-confound-past-health). If the bias and its incidence check out at primary, the note can move beyond seedling; the specific number or mechanism must not be inherited clean from Wikipedia.

Progress (2026-08-24) — partially answered, still open. A batch capture searched for a Tier 1–2 primary and did not fully close this. Findings: (1) an independent third telling — Bernstein, Against the Gods (1996), via a Goodreads-mediated transcription — corroborates the life-assurance-side direction (claim-bernstein-1996-corroborates-price-table-underestimated-life-expectancy) and, in the same passage, complicates the annuity-side incidence rather than confirming it (see the 2026-08-24 addendum on claim-price-northampton-table-overestimated-mortality-favouring-insurers); (2) the Tier 1–2 primary most likely to settle this — William Sutton, "On the Method used by Dr. Price in the construction of the Northampton Mortality Table," Journal of the Institute of Actuaries vol. 18 (1874), pp. 107–122 (see entity-william-sutton) — is now identified but was not accessible this session: Cambridge Core serves only its opening sentence ("Temporarily unavailable" for the body), the JSTOR mirror would not render, and the Internet Archive's JIA holdings skip volume 18 among the neighbouring volumes it does hold. Still open; still needs a direct read of Sutton 1874, Price's own Observations on Reversionary Payments, or Ogborn 1962 (see entity-m-e-ogborn).

Progress (2026-09-16) — still open, no read obtained, but the access picture is sharper. A renewed, dedicated session re-tested all three 2026-08-24 routes with fresh receipted fetches and tried two more not previously logged. Cambridge Core and the JSTOR mirror both still fail exactly as before (see entity-william-sutton for receipts); separately, JSTOR's own "Early Journal Content" free-access program is explicitly scoped to material published before 1923 in the US or before 1870 elsewhere, so it would not cover this 1874 British article even if it rendered. The Internet Archive gap at volume 18 now holds across three independently-catalogued digitization sets, not one, strengthening that finding from a single data point to a pattern. Two new routes: a full-view Google Books scan of the exact volume exists but is blocked to automated retrieval by a CAPTCHA wall rather than a paywall or missing holding — the first route in this chain that looks plausibly clearable by a human rather than genuinely inaccessible (see claim-jia-volume-18-google-books-scan-exists-but-captcha-blocks-automated-retrieval) — and HathiTrust's catalog and full-text search pages both 403'd outright, a fifth failure. No tool available this session could read Sutton's text. Candidate next moves, in rough order of promise: clear the Google Books CAPTCHA by hand; pursue institutional HathiTrust access; check the IFoA's own "List of available journals" and pre-1901 library catalogue PDFs (actuaries.org.uk) for a physical/interlibrary-loan holding of the Institute's own historical journal run — both unread past their opening pages this session (see entity-institute-and-faculty-of-actuaries).