FA-63799 / Actuarial life tables / Member archive

Cohort rates from a period table: Years beyond the table are rejected · case 04

Recent cohorts cannot be projected.

Member previewVariant 4 · 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 runs past last year	`"missing year 2016"`	`[[472, 476, 480, 484, 488, 492, 499, 506, 513, 520, 527], 0.94676348]`	Failed

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