From b040fc060da108ec773074976fd7061bf560c556 Mon Sep 17 00:00:00 2001 From: Vahid Ahmadi Date: Wed, 27 May 2026 10:17:07 +0200 Subject: [PATCH 1/2] Date Marriage Allowance take-up from 2015-04-06 (#623) The take-up parameter previously started at 2000-01-01, decades before the allowance existed (the allowance was inserted by Finance Act 2014 Sch. 2 and came into force 6 April 2015). Move the effective date to that introduction date, document the 0.5 value as the post-2019 steady state (per HoC Library SN00870, which notes outturn costs were consistently below forecast in the early years because take-up ramped up slowly), and add the HMRC Marriage Allowance statistics page as a third reference. --- .../allowances/marriage_allowance/takeup_rate.yaml | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/policyengine_uk/parameters/gov/hmrc/income_tax/allowances/marriage_allowance/takeup_rate.yaml b/policyengine_uk/parameters/gov/hmrc/income_tax/allowances/marriage_allowance/takeup_rate.yaml index 5a21633ac..3afd65a48 100644 --- a/policyengine_uk/parameters/gov/hmrc/income_tax/allowances/marriage_allowance/takeup_rate.yaml +++ b/policyengine_uk/parameters/gov/hmrc/income_tax/allowances/marriage_allowance/takeup_rate.yaml @@ -1,11 +1,13 @@ -description: Share of eligible couples who claim Marriage Allowance. HMRC outturn shows ~2.1m claimants vs ~4.2m eligible couples (~50% take-up). The matching parameter in policyengine-uk-data (`parameters/take_up/marriage_allowance.yaml`) is the load-bearing one for microsimulation, applied stochastically when populating `would_claim_marriage_allowance` per person; this file should be kept in sync. +description: Share of eligible couples who claim Marriage Allowance. HMRC outturn shows ~2.1m claimants vs ~4.2m eligible couples (~50% take-up) at steady state; take-up was materially lower in the first few years after the allowance was introduced in April 2015 (HMRC outturn costs ran consistently below original forecast for this reason). 0.5 is therefore the post-2019 steady-state rate. The matching parameter in policyengine-uk-data (`parameters/take_up/marriage_allowance.yaml`) is the load-bearing one for microsimulation, applied stochastically when populating `would_claim_marriage_allowance` per person; this file should be kept in sync. values: - 2000-01-01: 0.5 + 2015-04-06: 0.5 metadata: unit: /1 label: Marriage Allowance take-up rate reference: - - title: Income Tax Act 2007 s. 55B + - title: Income Tax Act 2007 s. 55B (inserted by Finance Act 2014 Sch. 2) href: https://www.legislation.gov.uk/ukpga/2007/3/section/55B - title: House of Commons Library — Income tax allowances for married couples (SN00870) - href: https://commonslibrary.parliament.uk/research-briefings/sn00870/ \ No newline at end of file + href: https://commonslibrary.parliament.uk/research-briefings/sn00870/ + - title: HMRC — Marriage Allowance statistics + href: https://www.gov.uk/government/statistics/marriage-allowance-statistics \ No newline at end of file From a7c4cc7f299eec7012f03d1453f139fae9f1e4ee Mon Sep 17 00:00:00 2001 From: Vahid Ahmadi Date: Wed, 27 May 2026 10:17:41 +0200 Subject: [PATCH 2/2] Add changelog entry for #623 take-up date fix --- changelog.d/623-takeup-start-date.md | 1 + 1 file changed, 1 insertion(+) create mode 100644 changelog.d/623-takeup-start-date.md diff --git a/changelog.d/623-takeup-start-date.md b/changelog.d/623-takeup-start-date.md new file mode 100644 index 000000000..b0247225e --- /dev/null +++ b/changelog.d/623-takeup-start-date.md @@ -0,0 +1 @@ +- Date the Marriage Allowance take-up rate parameter from 2015-04-06 (when the allowance came into force) rather than 2000-01-01, document that 0.5 is the post-2019 steady-state value, and link the HMRC Marriage Allowance statistics page.