FA-63795 / Actuarial life tables / Member archive

Cohort rates from a period table: Cohort rates read one calendar year · case 05

Cohort rates show no calendar-year effect.

Member previewVariant 5 · 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	`[[511, 518, 525, 532, 539, 546, 553], 0.96334904]`	`[[511, 515, 519, 523, 527, 531, 535], 0.96395941]`	Failed

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