How it works — Areivim UK risk model

For members

What each family would need to contribute.

The chart projects the average monthly collection needed per family, including an allowance for unpaid funds. Wedding and parent commitments are shown separately from monthly child support. Change the assumptions to compare possible schemes.

Full funding assumed

The model assumes 100% of the required amount is collected, plus a default 5% allowance for unpaid funds. The monthly limit is an editable comparison point, starting at £40.

♥

Compare child support

£400 and £600 per child per month are options under consideration. When support starts, it replaces the surviving-parent fund for new claims. Wedding funds remain separate, for unmarried children through age 35.

∞

Test the assumptions

Membership growth, marriage timing and mortality affect the result. Annual averages help compare options; they do not show monthly peaks or prove that a chosen collection limit will be sufficient.

Required collection per family per month, including allowance

2026 · today

Wedding + parent funds when support is off · with allowance Monthly child support · with allowance Child support launch year

View year Slide back to 2012 or forward to 2100. Green is wedding commitments plus parent commitments for claims before support starts or while it is disabled; gold is monthly child support. Both include the unpaid-funds allowance. Their total is the required collection per family, averaged across twelve months. 2026 · today

Each box shows its trend across the century — click any one for the full graph.

What this is based on

The assumptions behind the projection.

Every figure above comes from these inputs. They are read-only here — to change any of them, open the Advanced model below.

Member families today6,921

New families / year (assumed)400

Average age at joining28.1 yrs

Average children per family6.5

Wedding benefit per child£40,000

Surviving-parent benefitReplaced by child support from launch

Monthly child support£600 / child, until age 21

Child support startsAugust 2026

Required collection100% funding + 5%; compare with £40 / month

Chance of a lossGompertz; see live historical comparison

Wedding eligibilityUnmarried through age 35; timing assumption editable

Historical comparison2012–2025; repository-reported figures

Projection range2010–2100, today’s money

Advanced · the parameters

Every assumption, open to change.

Adjust these inputs to update the projection and historical comparison. Defaults combine figures reported in the repository with planning assumptions. £400 and £600 monthly support, and the £40 collection limit, are options to test.

📋 Membership & signups Real JoinDate counts from the membership export, with the 196 cancelled memberships removed — 6,921 active families. Bars are signups 2013→2026 (the 2012 founding year is left off for scale); the gold line is the true average across all years, the purple line the future-inflow assumption. fixed · real data

Total signups Every active family across all years — 6,921 (7,117 ever enrolled, less 196 cancelled).

Average / year Average signups per year, excluding the 2012 founding year (a one-off mass enrolment that would skew it) — so it reflects a typical year (≈303).

Future signups / yr Assumed new families joining each year going forward (affects years after today). 400 (a little above the recent average). More young joiners holds the cost per family down.

Future mean age The average signup age assumed for future joiners — kept at today’s 28.1.

Age at signup · empirical

Mean age Average age of an adult when their family joins. 28.1 is the pooled mean of 2,061 applicant + spouse ages from the dated records (applicant 28.6, spouse 27.6).

Spread (± yrs) Standard deviation of signup age — 7.4 in the data. It sets how wide the joining-age range is around the mean.

💀 Mortality & children model

Gompertz α Baseline mortality level in q(age)=1−e^(−α·e^(β·age)). The central setting α≈0.00001360040894 is fitted to the reported 55 historical losses using the default demography. The default adds 20% to that parameter. This is a count-only fit, not independent validation. The live historical comparison shows the effect of your selected mortality and demographic settings.

Gompertz β How fast risk accelerates with age. β=0.085 means the underlying mortality intensity doubles every ~8 years (ln2÷0.085). The live historical table compares the modeled parent age at loss with the repository-reported age of about 50.

Drop from pool at age Members are removed from the modelled pool once they reach this age (cover assumed to lapse). Default 75.

🧒 Having children

Avg children per family Completed family size. Children are assumed to arrive from parent age 22, spaced 2.4 years apart. Wedding eligibility and monthly-support age are calculated separately. Compare the resulting historical eligible-child count and mean age with the reported figures below; these assumptions are not independently validated. Model’s pool-wide average age of all born children: —. 6.5

First child at age The parent’s age when their first child is born. The model spaces the remaining children from here, which sets how many are still unmarried at any given age. Default 22.

Years between children Average gap between births. This affects children’s ages at a parent’s loss and the duration of monthly support. Default 2.4; check its effect in the live historical comparison.

♔ Benefit & orphan support levers

Benefit per child Committed on a first parent loss for each unmarried child through age 35. The parent fund uses the same amount, but only for claims before monthly support launches or while support is disabled. After launch, child support replaces the parent fund. £40,000

Unmarried share at ages 21–34 (%)

Actual age-at-marriage data is unavailable. The default 100% unmarried at ages 21–34 is an upper-bound stress assumption, not a measured marriage pattern. Ages 0–20 are assumed unmarried; at age 35, 1% remain unmarried, reflecting the assumption that 99% marry by 35. Wedding eligibility expires at 36.

Orphan monthly support · replaces parent fund

Per orphan, monthly Compare £400 and £600 per child per month. Set £0 to disable support and retain the parent fund. With support enabled, it replaces the parent fund for new claims from launch; the wedding benefit remains. Support cash uses eligible child-months, allowing for the launch month, losses during the year and the cutoff age. One child supported from birth draws up to £151,200. £600

Paid until age Children leave monthly support once they reach this age. Default 21. 21

Program starts Monthly support applies only to new eligible claims from the selected launch month and year. Claims earlier in the launch year retain the parent fund; later claims receive child support instead. The support roll builds until children reach the cutoff. 2026

Launch month (1 = January, 8 = August)

Collection assumptions

Monthly limit / family (£)

Unpaid-funds allowance (%)

Required collection = benefits committed + support cash, multiplied by 1 + the allowance. We assume this total is collected in full. The monthly limit is compared with the annual average; it does not reduce benefits or cap the calculation.

Advanced · historical comparison · 2012–2025

What the model reproduces — and what remains unverified.

Compare the current settings and the central mortality setting with the historical figures reported in the repository. The source exports are unavailable for independent verification. A central setting fitted to the loss count does not independently validate the number or ages of eligible children.

Historical measure	Repository-reported (unverified)	Central / default fit	Selected mortality
First parent losses	55	—	—
Wedding-eligible children at loss	220	—	—
Wedding-eligible children / claim	3.96	—	—
Wedding-eligible child mean age at loss	16.6 years	—	—
Support-age child mean age at loss	Unavailable	—	—
Parent mean age at loss	About 50 years	—	—

Wedding-eligible children and children under the monthly-support cutoff are different groups. The reported mean age of 16.6 cannot validate support duration without knowing which children were included. The reported 220 children and 55 losses imply 4.00 children per loss, rather than the separately reported 3.96; the source definitions need reconciliation.

Advanced · cost per family

Estimated losses and the cost per family

For each cohort, the model applies the estimated chance of a first parent loss to families that have not already been affected. Wedding commitments depend on unmarried children through age 35; monthly child support uses its separate cutoff. These benefits determine the required collection for the selected year.

The age of the membership

follows the year below

with wedding-eligible children no wedding-eligible children annual mortality by age

Estimating for year Drag to pick the year you’re estimating. Required collection per family includes the unpaid-funds allowance; the monthly figure is the annual average divided by 12, not a forecast of individual monthly bills. 2026 · today

Families in pool

—

Estimated first losses / yr

—

unaffected families × first-loss probability

New wedding-eligible orphans / yr

—

weighted by unmarried share through age 35

Orphans on support

—

still under cutoff at year end

Loss-per-family ratio

—

families ÷ estimated losses

Wedding + parent commitments / yr

—

parent fund replaced from support launch

Support cash / yr

—

eligible child-months × monthly support

Benefits committed + support cash / yr

—

before unpaid-funds allowance

Required collection / family / yr

—

including unpaid-funds allowance

Required collection / family / month

—

with allowance · annual average ÷ 12

Four programme-level trends across the century — each box tracks the selected year; click for the full graph.

Where the losses come from — rate by age band

Mortality is applied at each year of age. This table summarises families and expected first losses into age bands.

Age band	Families	Blended mortality	Est. losses/yr	% of losses

Blended mortality averages the single-life rate q across families in each band. Estimated losses apply 1−(1−q)² only to unaffected families; a surviving parent’s later death does not create a second fund.

Advanced · the century view

How does the required collection change over time?

Compare the projected annual average with your chosen monthly limit as the membership ages. Test different numbers of future joiners, support amounts and marriage assumptions above. The projection assumes full collection plus the allowance; it does not simulate monthly claim peaks or a reserve.

Required annual collection per family, 2010 → 2100

Century · 2010–2100

Wedding + parent funds when support is off · with allowance Monthly child support · with allowance Child support launch year

Advanced · 2010 → 2100

Losses, commitments, support and collections, year by year

Each box shows the figure for the selected year with its century trend behind it — click any one for the full graph.

Advanced · the method

Every figure, and how to check it

The formulas below use the age and benefit assumptions in the input panels. The projection tracks unaffected families for first claims and eligible months of support; the live historical table exposes differences from the reported experience.

Signups per year. The starting point is the annual membership counts reported in the repository, beginning in 2012. The underlying export is unavailable for verification.
Age at signup → date of birth. From dated records we know the typical joining age (~28). For anyone missing a date of birth we assign an estimated signup age, then DOB = signup year − signup age.
Age today. current age = signup age + years since joining. Ageing each cohort to today produces the histogram above.
Project the future. Cohorts age, members reaching the exit age leave, and new families join under the selected assumptions. Families already affected remain outside the first-claim population.
Losses → benefits. For unaffected families, the first-loss probability is 1 − (1 − q)². Wedding commitments use the expected unmarried children through age 35. Parent commitments apply only before child support launches or when it is disabled.
Support → collections. Monthly support starts only for new eligible claims from launch, and ends at the selected cutoff. Add annual support cash to benefits committed, apply the unpaid-funds allowance, then divide by member families and twelve for the required monthly average.

Mortality, one parent q(age) = 1 − e^(−α·e^(β·age))
First parent loss probability pₜ = 1 − (1 − q)², applied only to unaffected families.
Expected wedding-eligible children = born children weighted by the unmarried assumption: 100% at ages 0–20, the selected share at ages 21–34, 1% at age 35 and 0% from age 36.
First losses / yr = Σ unaffected families(age) × pₜ(age).
New wedding-eligible orphans / yr = Σ unaffected families(age) × pₜ(age) × expected wedding-eligible children.
Wedding commitments / yr = new wedding-eligible orphans × benefit. Parent commitments use the same benefit per first claim before support launch or with support disabled.
Support cash / yr = eligible child-months × monthly amount. New claims are spread through the year; launch timing and the support cutoff limit paid months.
Required collection / family / yr = (benefits committed + support cash) × (1 + allowance / 100) ÷ families. The monthly average is this figure ÷ 12.

Live worked example · one family at age 45, current settings

How old is our pool — and how much should each family pay?