FA-63793 / Actuarial life tables / Member archive

Cohort rates from a period table: Cohort rates read one calendar year · case 03

Cohort rates show no calendar-year effect.

Member previewVariant 3 · 3 implementations · 6 checks per implementation

Case contract

Input table {year: [q per 100000 by age from 0]}, cohort birth year, ages a0..a1. Cohort rate at age a is table[cohort+a][a]; years after the last tabulated year use the last year; years before the first -> 'missing year <y>'; missing ages -> 'missing age <a>'. Return [rates, survival over the ages rounded 8].

Why this case matters

Life-table arithmetic compounds across ages, so one misplaced index or assumption shifts every downstream value.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
cohort inside table	`[[509, 516, 523, 530, 537, 544, 551], 0.96348464]`	`[[509, 513, 517, 521, 525, 529, 533], 0.96409508]`	Failed

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