Cohort model

Observed age-band snapshots and a modelled 2026 to 2036 age-band transition scenario.

Observed Scenario

The cohort model is inferred from age-band snapshots, not longitudinal individual data. Public aggregate tables do not track the same individuals across time. Retention rates are assumptions.

Observed age bands

Observed

Age bands changed in 2025 when the early-childhood age limit expanded from under 7 to under 9. Bands before and after are not directly comparable.

Cohort sliders

Child entries per year estimated assumption 24,000 Share of child participants retained into adulthood estimated assumption 60% Band-boundary retention rate estimated assumption 95% Adult entries per year estimated assumption 30,000 65+ terminal retention rate estimated assumption 90%

Modelled 2026 to 2036 bands

Scenario

Assumption: each finite band ages out at 1/band width per year; adult entries are applied to the 19-24 band.

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