[juaristi22]

Fixes #2381

Hold reported Bereavement Support Payment (BSP) nominally flat when a dataset explicitly supplies both war_widows_pension_reported and widowed_parents_allowance_reported in the same source year. All-zero columns count as supplied inputs. Microcosm's merged #1383 writes both columns. BSP rates remain unchanged under article 19 of the 2026 up-rating order.

Older datasets can combine BSP with CPI-linked War Widow's Pension and Widowed Parent's Allowance. They retain CPI uprating, including datasets that separate only one benefit. Household situations retain their existing CPI behaviour. The separate allowance and war-widow inputs continue to grow with CPI, and the class-level BSP CPI declaration remains available to legacy consumers.

Apply the same two-input contract during automatic projection, in the Simulation/Microsimulation fallback after the materialised horizon, and when economic assumptions are disabled. The fallback checks both explicit inputs in the source period of the latest supplied BSP amount. Calculated defaults and inputs in different periods do not declare a completed split. Supplied annual amounts remain authoritative; disabling economic assumptions preserves a later BSP observation when either observation contains the complete split.

The published BSP plan, growth-factor page, dataset-source guidance and variable metadata describe this behaviour. The guide also records the producer's residual limitation: unclassified off-rate amounts can include Widowed Parent's Allowance with inherited additional pension, so holding that CPI-linked component flat understates it.

Reproducer: policyengine_uk/tests/test_bsp_dataset_projection.py::test_completed_split_freezes_bsp_in_each_projected_year; policyengine_uk/tests/test_bsp_dataset_projection.py::test_completed_split_freezes_bsp_after_the_projection_horizon; policyengine_uk/tests/test_bsp_dataset_projection.py::test_wpa_column_alone_preserves_legacy_cpi_uprating

The new guard regressions failed against the prior implementation: 12 failed and 19 passed before the fix. The fixture-scale tests use controlled CPI paths without private survey data. They cover complete and partial schemas, positive and zero inputs, same-period provenance, the 4 × 4 reset matrix, computed defaults, dependency invalidation for either input, monthly conversion, authoritative multi-year amounts, reform/baseline isolation, clones and rebuilds, structural overrides and cache opt-out.

axiom: n/a: dataset projection and backward-compatibility correction; statutory rates and entitlement rules are unchanged.

Validation:

• Exact 12-file targeted Python manifest: 263 passed after rebasing onto main at adbaa87d7 (282.13 seconds).
• uv run --frozen --no-sync policyengine-core test policyengine_uk/tests/policy/baseline/gov/dwp/widowed_parents_allowance.yaml -c policyengine_uk: 7 passed after rebasing.
• uv run --frozen --no-sync make format; post-rebase ruff format --check . and ruff check . pass.
• uv run --frozen --no-sync make documentation passed before and after rebasing.
• Independent fix verification: all four findings addressed, with no new findings.

The full certified-data suite was not run locally. CI runs the repository suite on the pushed head.

Targeted Python validation command

uv run --frozen --no-sync pytest \
  policyengine_uk/tests/test_bsp_dataset_projection.py \
  policyengine_uk/tests/test_projection_horizon.py \
  policyengine_uk/tests/test_widowed_parents_allowance.py \
  policyengine_uk/tests/test_war_widows_pension.py \
  policyengine_uk/tests/test_uprating_inputs_reach_data.py \
  policyengine_uk/tests/test_benefit_uprating_published.py \
  policyengine_uk/tests/code_health/test_uprating_declarations.py \
  policyengine_uk/tests/code_health/test_simulation_methods_defined_once.py \
  policyengine_uk/tests/code_health/test_changelog_fragments.py \
  policyengine_uk/tests/code_health/test_input_variable_definitions.py \
  policyengine_uk/tests/code_health/test_household_benefits_in_government_spending.py \
  policyengine_uk/tests/test_gov_spending_properties.py -q

[vahid-ahmadi]

@juaristi22 thanks, this is my review at e760e4c20.

Verdict. The approach is right, and better than the one I proposed in #2381. Keying the freeze on the dataset keeps legacy files on CPI, so the £84m error the issue warned about cannot happen for today's data. The law is right and the new tests do what the body says. Two shoulds: the trigger is the allowance column alone, which still lets a dataset freeze War Widow's Pension, and two docs pages now say the opposite of what the code does. CI is not finished yet (the Python test shards and Aggregate impact are still pending), so this is a comment, not an approval.

A mistake of ours first. Step 3 of #2381 said to drop bsp_reported from the CPI list and remove its uprating attribute once released datasets carry the split. That would have frozen every dataset, including the Enhanced FRS and older Microcosm releases that still hold codes 6 and 9 together. That is the £84m error again, just later. Your dataset-keyed design avoids it, and the class-level CPI declaration has to stay for legacy files. The issue text was wrong on this.

What I checked

• Law. SI 2017/410 reg 3 still reads £350, £3,500, £100 and £2,500. SI 2026/148 art 19 says each "remains unchanged", and art 18 raises Widowed Parent's Allowance from £150.90 to £156.65. The GOV.UK BSP page shows the same amounts. So the body's line "rates remain unchanged under article 19 of the 2026 up-rating order" is accurate, and art 19 is the right citation.
• Producer. At microcosm#1383 head e570d65ff, frs_spine.py writes widowed_parents_allowance_reported for every person from _sum_to_entity(amount * wpa, ...), so a person with no allowance gets 0. The name matches exactly, the column is in the frame's person column list and in the terminal coverage list, and war_widows_pension_reported is written alongside it.
• Legacy path. With no allowance column, bsp_reported keeps CPI in the projector, after the horizon and when economic assumptions are off (test_missing_wpa_column_preserves_legacy_cpi_uprating, legacy and partial-split cases). A calculated default allowance does not switch it on (test_calculating_default_wpa_does_not_migrate_a_legacy_dataset).
• Tests. At the head, test_bsp_dataset_projection.py, test_projection_horizon.py, test_widowed_parents_allowance.py, test_war_widows_pension.py, test_uprating_inputs_reach_data.py, test_benefit_uprating_published.py and the code-health uprating, simulation-method, changelog, input-definition and spending tests: 228 passed. Against the merge base b1fb356cc, the new file gives 25 failed and 12 passed. The 12 that pass are the legacy and household cases, which should pass on both. Both Reproducer tests fail on the base for the positive and zero allowance cases.
• Edge cases in simulation.py:1363-1401. The fallback is skipped for a formula or neutralised override, for a non-CPI uprating, for situations and for periods that are themselves inputs. It takes the latest earlier annual input and reads the allowance input for that same period. Monthly output is divided once. Reforms and baselines both see the split. I found no case where it misfires.
• Merge order. The branch merges cleanly with main (4 commits ahead, none in these files). Of the open PRs touching the same files, #2627, #2635, #2638, #2639 and #2265 merge cleanly with this head. #2589, #2131, #2002, #2077 and #1969 already conflict with main, so nothing new comes from this PR.

Findings

1. should, policyengine_uk/simulation.py:1394-1399, policyengine_uk/data/economic_assumptions.py:345-349 and :855-858. The split is declared by widowed_parents_allowance_reported alone. test_bsp_dataset_projection.py:123 (test_wpa_column_alone_signals_the_completed_split) fixes that on purpose with no war-widow column. But a dataset that splits the allowance out before it moves FRS code 9 still has War Widow's Pension in bsp_reported, about 90% of its value in the raw FRS. policyengine-uk-data#578 asks for the code 9 move first, so this needs that order to be reversed or a third-party dataset, but nothing in the model stops it. Such a dataset would freeze the pension, which is the £84m case from #2381. This is a cheap guard rather than a likely path. Requiring both war_widows_pension_reported and widowed_parents_allowance_reported costs nothing for Microcosm, which writes both. That test would then flip to keep CPI.
2. should, docs/book/programs/gov/dwp/bereavement-support-plan.md:56-66 still says bsp_reported "keeps CPI uprating only until the datasets move FRS code 9 out of it and WPA into widowed_parents_allowance_reported", that microcosm#1222 is open, and that #2381 "tracks freezing it after that". After this PR that is out of date. docs/book/assumptions/growthfactors.md:23 also lists bsp_reported among the CPI variables without the exception. A short line pointing to the new section in dataset-sources.md would fix both.
3. nit, policyengine_uk/variables/gov/dwp/war_widows_pension.py:18-20 says "the datasets still add it to bsp_reported (policyengine-uk-data#578, microcosm#1222)". For Microcosm that stopped with microcosm#1333. It would be worth correcting while you are in this area.
4. nit, docs/engineering/skills/dataset-sources.md:138-139. Off-rate amounts kept in split bsp_reported are held flat. microcosm#1383 says these include an allowance with an inherited additional pension above the allowance rate, which rises with CPI. In the raw FRS 2024-25 the whole off-rate bucket is about £7m a year, so the effect is small. Saying in one clause that this part is understated would make the guide complete.

Aggregate effect. On today's released data, which has no allowance column, nothing changes, so the Aggregate impact job should show zero. For a release built from microcosm#1383, the change removes CPI growth from BSP alone. Using the model's CPI path from a 2024 base (cumulative factor 1.058 in 2026-27, 1.079 in 2027-28, 1.100 in 2028-29 and 1.122 in 2029-30) on the roughly £100m a year of raw FRS 2024-25 code 6 at BSP rates, spending is lower by about £6m in 2026-27, £8m in 2027-28, £10m in 2028-29 and £12m in 2029-30, or up to about £13m if all off-rate amounts are included. A calibrated release will give a somewhat different base.

PR body and changelog. The Reproducer tests exist and fail on the base. The axiom: n/a reason fits a projection change with no change to rates or rules. changelog.d/2381.fixed.md describes the change accurately.

🤖 Generated with Claude Code

[github-actions]

Aggregate impact on certified data: pass

Base adbaa87d79 against head 4480048c6a, both on enhanced_frs_2024_25.h5 (policyengine-uk-data 1.58.1, sha256 056e80fd8e91), fiscal years 2025-26 to 2031-32. Each year is a full microsimulation run on each side.

Checks: 0 broken by this change, 1 failing on both sides, 0 fixed. Moves flagged for review: 0 (thresholds in report_spec.yaml; a flag does not fail the job).

Workflow run and full report

Notes

• In the years a figure from fewer than 10 records is suppressed (spending.disabled_students_allowance), every total containing it, and the decile incomes, are rebuilt from their other components, so no published total includes it. Those totals are marked †. A change is withheld where the two sides leave out different figures and can't be lined up.

Moves flagged for review

None.

Spending by benefit and service

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed

Caseloads

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed

Standard reform costings (change in gov_balance)

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise additional rate by 3pp	0	0	0	0	0	suppressed	suppressed

Standard reforms: change in each reform's target

Measure	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise additional rate by 3pp: change in income_tax	0	0	0	0	0	suppressed	suppressed

Household net income by decile

No household's net income changes in any year.

No change in any year: receipts by tax head; government balance, each component counted once; model totals; household income totals; population; poverty rates; people in poverty; inequality; mean household net income in each side's own deciles.

Checks failing on both base and head (1)

• VAT is never negative (sign:vat): 2025-26: 76 units below zero, a weighted £-54,346,675 in total; 2026-27: 76 units below zero, a weighted £-55,887,703 in total; 2027-28: 76 units below zero, a weighted £-57,090,734 in total

Counted-once check

Each of 87 components was raised by £1 per unit in 2026-27, and every head of its totals was read household by household: its own head must rise by exactly £1, no other tax head may move, no other benefit may rise, and the model's own total must move by what its heads moved. A head that breaks a rule is measured again twice: with every other head held at its baseline value, and with every other head held at its value after the first £1 while the component rises again. It fails where either still shows the response. 0 failed; 0 were skipped.

• widowed_parents_allowance: pension_credit responds only through other heads in fewer than 10 households (other heads that moved there: carers_allowance; gov_spending; not a failure)
• widowed_parents_allowance: pension_credit responds only through other heads in fewer than 10 households (other heads that moved there: carers_allowance; household_benefits; not a failure)

Provenance

Side	Commit	Runtime	Environment hash	Partition hash	Time
base	main adbaa87d79	uk 2.156.0 (files 39e6300c1bcf), core 3.33.2, py 3.13.17 aarch64	6e908e96b696	06ff679de152	1653.19s
head	#2644 merged into main 4480048c6a	uk 2.156.0 (files 9788872bca71), core 3.33.2, py 3.13.17 aarch64	6e908e96b696	06ff679de152	1675.31s

Dataset: hf://policyengine/policyengine-uk-data-private/enhanced_frs_2024_25.h5@2526edbbb687a3b54dbb11272e5389e4b62d2ac2, sha256 056e80fd8e9151d78f432a25cde863340baee81304c6216a37fb575ce8563784 (verified on both sides), policyengine-uk-data 1.58.1.

Receipts by tax head: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Income tax	£298.41bn	£318.00bn	£335.26bn	£350.17bn	£365.42bn	£383.13bn	£400.61bn
National Insurance (employee and self-employed)	£52.37bn	£54.71bn	£56.48bn	£58.15bn	£60.22bn	£62.11bn	£64.44bn
National Insurance (employer)	£152.00bn	£158.47bn	£163.28bn	£167.71bn	£174.87bn	£180.28bn	£187.05bn
Employer NI change borne by capital	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Employer NI change borne by consumers	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Capital gains tax	£12.61bn	£13.05bn	£13.53bn	£14.02bn	£14.52bn	£15.05bn	£15.58bn
Student loan repayments	£7.79bn	£8.09bn	£8.31bn	£8.51bn	£8.72bn	£8.97bn	£9.28bn
VAT	£251.45bn	£257.40bn	£263.96bn	£270.05bn	£276.34bn	£282.83bn	£289.13bn
Change in VAT from its baseline	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
VAT on private school fees	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Fuel duties	£24.53bn	£24.64bn	£26.64bn	£26.69bn	£26.42bn	£25.76bn	£26.35bn
Alcohol duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Tobacco duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Vehicle excise duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Betting and gaming duties	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
TV licence fee	£4.26bn	£4.41bn	£4.42bn	£4.44bn	£4.45bn	£4.47bn	£4.48bn
Council tax	£49.21bn	£51.88bn	£54.97bn	£58.29bn	£61.55bn	£64.92bn	£68.49bn
High value council tax surcharge	£0.00bn	£0.00bn	£0.00bn	£0.48bn	£0.49bn	£0.50bn	£0.51bn
Northern Ireland domestic rates	£0.55bn	£0.58bn	£0.60bn	£0.63bn	£0.66bn	£0.69bn	£0.72bn
Business rates	£34.68bn	£38.04bn	£38.88bn	£39.76bn	£43.07bn	£43.13bn	£44.57bn
Stamp duty land tax on the household's own purchases	£6.90bn	£7.39bn	£7.81bn	£8.21bn	£8.62bn	£9.02bn	£9.42bn
Stamp duty land tax paid by companies	£4.81bn	£5.98bn	£6.73bn	£7.46bn	£8.21bn	£8.87bn	£9.16bn
Land transaction tax (Wales)	£0.07bn	£0.08bn	£0.09bn	£0.09bn	£0.10bn	£0.10bn	£0.11bn
Land and buildings transaction tax (Scotland)	£0.31bn	£0.32bn	£0.34bn	£0.35bn	£0.37bn	£0.38bn	£0.40bn
Unspecified tax change borne by capital	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Unspecified tax change borne by consumers	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Wealth tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Wealth tax excluding the main residence	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Land value tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Carbon tax	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Spending by benefit and service: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
State Pension	£121.64bn	£126.07bn	£127.08bn	£128.87bn	£132.52bn	£136.31bn	£140.08bn
Pension Credit	£6.66bn	£7.04bn	£7.32bn	£7.46bn	£7.60bn	£7.77bn	£7.94bn
Winter Fuel Payment	£1.69bn	£1.67bn	£1.58bn	£1.56bn	£1.56bn	£1.54bn	£1.51bn
Pension Age Winter Heating Payment (Scotland)	£0.19bn	£0.20bn	£0.20bn	£0.21bn	£0.21bn	£0.22bn	£0.22bn
Universal Credit	£75.21bn	£80.38bn	£82.93bn	£84.23bn	£85.58bn	£86.87bn	£87.97bn
Housing Benefit	£8.55bn	£8.89bn	£9.17bn	£9.31bn	£9.57bn	£9.83bn	£10.10bn
Council Tax Reduction	£1.98bn	£2.02bn	£2.07bn	£2.11bn	£2.16bn	£2.21bn	£2.25bn
Employment and Support Allowance (income-related)	£0.79bn	£0.81bn	£0.83bn	£0.85bn	£0.86bn	£0.89bn	£0.90bn
Employment and Support Allowance (contribution-based)	£5.20bn	£5.34bn	£5.46bn	£5.59bn	£5.72bn	£5.85bn	£5.99bn
Jobseeker's Allowance (income-based)	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Jobseeker's Allowance (contribution-based)	£0.29bn	£0.30bn	£0.30bn	£0.31bn	£0.32bn	£0.32bn	£0.33bn
Income Support	£0.12bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Working Tax Credit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Child Tax Credit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Incapacity Benefit	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Personal Independence Payment	£26.94bn	£28.06bn	£29.13bn	£29.83bn	£30.54bn	£31.26bn	£31.96bn
Disability Living Allowance	£7.49bn	£7.80bn	£8.10bn	£8.29bn	£8.49bn	£8.69bn	£8.88bn
Attendance Allowance	£8.68bn	£9.04bn	£9.38bn	£9.61bn	£9.83bn	£10.07bn	£10.29bn
Carer's Allowance	£4.48bn	£4.67bn	£4.84bn	£4.96bn	£5.08bn	£5.19bn	£5.31bn
Carer Support Payment (Scotland)	£0.31bn	£0.32bn	£0.33bn	£0.34bn	£0.35bn	£0.36bn	£0.37bn
Carer's Allowance Supplement (Scotland)	£0.00bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn
Severe Disablement Allowance	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn	£0.03bn
Industrial Injuries Disablement Benefit	£0.50bn	£0.52bn	£0.53bn	£0.54bn	£0.55bn	£0.57bn	£0.58bn
Armed Forces Compensation Scheme	£0.61bn	£0.62bn	£0.64bn	£0.65bn	£0.67bn	£0.68bn	£0.70bn
War Widow's or Widower's Pension	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Child Benefit	£16.16bn	£16.83bn	£17.43bn	£17.85bn	£18.26bn	£18.69bn	£19.10bn
Scottish Child Payment	£0.49bn	£0.52bn	£0.54bn	£0.55bn	£0.56bn	£0.57bn	£0.56bn
Two Child Limit Payment (Scotland, counterfactual)	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Healthy Start vouchers	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn	£0.05bn
Maternity Allowance	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Statutory Maternity Pay	£3.30bn	£3.39bn	£3.47bn	£3.55bn	£3.63bn	£3.72bn	£3.80bn
Statutory Paternity Pay	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Statutory Sick Pay	£1.12bn	£1.15bn	£1.18bn	£1.21bn	£1.24bn	£1.27bn	£1.29bn
Sure Start Maternity Grant	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn	£0.01bn
Bereavement Support Payment	£0.67bn	£0.69bn	£0.70bn	£0.72bn	£0.73bn	£0.75bn	£0.77bn
Widowed Parent's Allowance	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Tax-Free Childcare	£0.55bn	£0.56bn	£0.57bn	£0.58bn	£0.59bn	£0.61bn	£0.59bn
Extended childcare entitlement	£2.76bn	£3.25bn	£3.35bn	£3.41bn	£3.50bn	£3.58bn	£3.67bn
Universal childcare entitlement	£2.25bn	£2.44bn	£2.50bn	£2.56bn	£2.63bn	£2.70bn	£2.76bn
Targeted childcare entitlement	£0.47bn	£0.49bn	£0.49bn	£0.51bn	£0.52bn	£0.53bn	£0.47bn
Childcare Offer for Wales	£0.26bn	£0.28bn	£0.28bn	£0.29bn	£0.30bn	£0.30bn	£0.31bn
Care to Learn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Childcare Grant	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Parents' Learning Allowance	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn	£0.20bn
Adult Dependants' Grant	£0.06bn	£0.06bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn	£0.04bn
Travel Grant	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed
16 to 19 Bursary Fund	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
NHS spending	£203.83bn	£204.54bn	£205.13bn	£205.79bn	£206.49bn	£207.23bn	£207.73bn
State education spending	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn	£0.02bn
Transport subsidy spending	£25.05bn	£25.13bn	£25.21bn	£25.29bn	£25.37bn	£25.46bn	£25.53bn
Cost-of-living support payment	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Energy Bills Rebate	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Energy Price Guarantee subsidy	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Basic income	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Disability basic income	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn
Other public spending budget change	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Caseloads: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
State Pension	11,261k	11,158k	10,849k	10,746k	10,783k	10,822k	10,848k
Pension Credit	1,485k	1,483k	1,480k	1,461k	1,462k	1,464k	1,460k
Winter Fuel Payment	7,061k	6,979k	6,565k	6,472k	6,446k	6,328k	6,184k
Pension Age Winter Heating Payment (Scotland)	803k	803k	803k	800k	803k	806k	808k
Universal Credit	6,334k	6,341k	6,366k	6,347k	6,345k	6,333k	6,298k
Housing Benefit	1,249k	1,247k	1,250k	1,234k	1,238k	1,240k	1,239k
Council Tax Reduction	3,174k	3,198k	3,208k	3,228k	3,243k	3,256k	3,263k
Employment and Support Allowance (income-related)	71k	71k	71k	71k	71k	72k	72k
Employment and Support Allowance (contribution-based)	719k	721k	723k	726k	728k	731k	732k
Jobseeker's Allowance (income-based)	0k	0k	0k	0k	0k	0k	0k
Jobseeker's Allowance (contribution-based)	67k	67k	67k	68k	68k	68k	68k
Income Support	25k	0k	0k	0k	0k	0k	0k
Working Tax Credit	0k	0k	0k	0k	0k	0k	0k
Child Tax Credit	0k	0k	0k	0k	0k	0k	0k
Incapacity Benefit	0k	0k	0k	0k	0k	0k	0k
Personal Independence Payment	3,566k	3,579k	3,589k	3,601k	3,613k	3,626k	3,635k
Disability Living Allowance	1,291k	1,295k	1,299k	1,303k	1,308k	1,312k	1,316k
Attendance Allowance	1,694k	1,700k	1,705k	1,711k	1,716k	1,723k	1,727k
Carer's Allowance	1,034k	1,038k	1,041k	1,044k	1,048k	1,051k	1,053k
Carer Support Payment (Scotland)	71k	71k	72k	72k	72k	72k	73k
Carer's Allowance Supplement (Scotland)	0k	71k	72k	72k	72k	72k	73k
Severe Disablement Allowance	4k	4k	4k	4k	4k	4k	4k
Industrial Injuries Disablement Benefit	137k	137k	138k	138k	139k	139k	140k
Armed Forces Compensation Scheme	93k	93k	94k	94k	94k	95k	95k
War Widow's or Widower's Pension	0k	0k	0k	0k	0k	0k	0k
Child Benefit	8,102k	8,128k	8,142k	8,165k	8,191k	8,216k	8,232k
Scottish Child Payment	350k	352k	353k	357k	354k	355k	342k
Two Child Limit Payment (Scotland, counterfactual)	0k	0k	0k	0k	0k	0k	0k
Healthy Start vouchers	199k	200k	201k	201k	202k	203k	203k
Maternity Allowance	0k	0k	0k	0k	0k	0k	0k
Statutory Maternity Pay	332k	334k	335k	336k	337k	338k	339k
Statutory Paternity Pay	0k	0k	0k	0k	0k	0k	0k
Statutory Sick Pay	181k	182k	182k	183k	183k	184k	185k
Sure Start Maternity Grant	26k	26k	26k	26k	26k	27k	27k
Bereavement Support Payment	98k	98k	98k	99k	99k	99k	100k
Widowed Parent's Allowance	0k	0k	0k	0k	0k	0k	0k
Tax-Free Childcare	1,014k	1,024k	1,024k	1,027k	1,027k	1,031k	1,013k
Extended childcare entitlement	715k	722k	725k	727k	733k	735k	736k
Universal childcare entitlement	982k	985k	987k	991k	996k	1,004k	1,005k
Targeted childcare entitlement	98k	97k	95k	95k	96k	96k	84k
Childcare Offer for Wales	39k	39k	39k	39k	39k	39k	39k
Care to Learn	0k	0k	0k	0k	0k	0k	0k
Childcare Grant	0k	0k	0k	0k	0k	0k	0k
Parents' Learning Allowance	98k	98k	99k	99k	99k	100k	100k
Adult Dependants' Grant	18k	18k	12k	12k	12k	13k	13k
Travel Grant	0k	0k	0k	0k	0k	0k	0k
Disabled Students' Allowance	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed	suppressed
16 to 19 Bursary Fund	0k	0k	0k	0k	0k	0k	0k
Cost-of-living support payment	0k	0k	0k	0k	0k	0k	0k
Energy Bills Rebate	0k	0k	0k	0k	0k	0k	0k
Energy Price Guarantee subsidy	0k	0k	0k	0k	0k	0k	0k
Basic income	0k	0k	0k	0k	0k	0k	0k
Disability basic income	0k	0k	0k	0k	0k	0k	0k

Government balance, each component counted once: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Government receipts, each component once	£899.96bn	£943.04bn	£981.29bn	£1,015.02bn	£1,054.03bn	£1,090.23bn	£1,130.30bn
Government spending	£528.63bn †	£543.42bn †	£551.15bn †	£557.43bn †	£565.84bn †	£574.45bn †	£582.36bn †
Government balance, each receipt once	£371.33bn †	£399.62bn †	£430.14bn †	£457.59bn †	£488.19bn †	£515.78bn †	£547.95bn †
Benefits in household_benefits but not in gov_spending	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn	£0.00bn

Model totals: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
gov_tax	£899.96bn	£943.04bn	£981.29bn	£1,015.02bn	£1,054.03bn	£1,090.23bn	£1,130.30bn
household_tax	£496.50bn	£527.17bn	£554.05bn	£577.26bn	£602.82bn	£627.12bn	£654.13bn
pre_budget_change_household_tax	£488.71bn	£519.08bn	£545.75bn	£568.28bn	£593.61bn	£617.65bn	£644.33bn
gov_spending	£528.63bn †	£543.42bn †	£551.15bn †	£557.43bn †	£565.84bn †	£574.45bn †	£582.36bn †
household_benefits	£528.63bn †	£543.42bn †	£551.15bn †	£557.43bn †	£565.84bn †	£574.45bn †	£582.36bn †
gov_balance	£371.33bn †	£399.62bn †	£430.14bn †	£457.59bn †	£488.19bn †	£515.78bn †	£547.95bn †

Household income totals: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Household market income	£1,651.49bn	£1,713.03bn	£1,764.05bn	£1,812.97bn	£1,862.19bn	£1,918.39bn	£1,985.28bn
Household net income	£1,644.51bn †	£1,688.72bn †	£1,719.48bn †	£1,750.46bn †	£1,781.44bn †	£1,820.74bn †	£1,866.93bn †
Household net income (HBAI definition)	£1,457.74bn	£1,504.86bn	£1,537.87bn	£1,569.56bn	£1,602.79bn	£1,640.51bn	£1,686.67bn

Population: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
People	69,224k	69,466k	69,668k	69,891k	70,128k	70,381k	70,550k
Benefit units	35,100k	35,223k	35,325k	35,438k	35,558k	35,686k	35,772k
Households	31,037k	31,145k	31,236k	31,336k	31,442k	31,555k	31,631k

Poverty rates: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Absolute poverty, before housing costs: everyone	16.0%	15.1%	15.5%	15.6%	15.7%	15.7%	15.8%
Absolute poverty, before housing costs: children	24.0%	21.1%	21.5%	21.5%	21.7%	21.7%	21.8%
Absolute poverty, before housing costs: working-age adults	13.8%	13.5%	14.0%	14.1%	14.2%	14.2%	14.3%
Absolute poverty, before housing costs: pensioners	13.6%	13.2%	13.1%	13.4%	13.5%	13.5%	13.5%
Absolute poverty, after housing costs: everyone	21.4%	20.8%	21.2%	21.5%	21.8%	21.9%	22.2%
Absolute poverty, after housing costs: children	33.0%	30.7%	31.0%	31.1%	31.4%	31.7%	32.3%
Absolute poverty, after housing costs: working-age adults	19.8%	19.6%	20.2%	20.5%	20.7%	20.9%	21.1%
Absolute poverty, after housing costs: pensioners	12.7%	12.3%	12.3%	12.5%	12.9%	12.9%	13.0%
Relative poverty, before housing costs: everyone	17.2%	16.4%	16.5%	16.4%	16.3%	16.4%	16.6%
Relative poverty, before housing costs: children	26.2%	23.5%	23.4%	23.1%	22.8%	23.0%	23.3%
Relative poverty, before housing costs: working-age adults	14.6%	14.3%	14.7%	14.7%	14.6%	14.7%	14.9%
Relative poverty, before housing costs: pensioners	15.0%	14.8%	14.1%	14.1%	14.0%	14.0%	14.2%
Relative poverty, after housing costs: everyone	21.6%	21.0%	21.2%	21.2%	21.3%	21.4%	21.8%
Relative poverty, after housing costs: children	33.2%	31.2%	30.9%	30.7%	31.0%	31.0%	31.5%
Relative poverty, after housing costs: working-age adults	19.9%	19.8%	20.1%	20.3%	20.4%	20.5%	20.7%
Relative poverty, after housing costs: pensioners	12.9%	12.4%	12.1%	11.9%	11.8%	11.9%	12.8%

People in poverty: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Absolute poverty, before housing costs: everyone	11,042k	10,465k	10,769k	10,890k	10,993k	11,057k	11,136k
Absolute poverty, before housing costs: children	3,579k	3,171k	3,230k	3,240k	3,280k	3,300k	3,324k
Absolute poverty, before housing costs: working-age adults	5,846k	5,744k	6,034k	6,134k	6,183k	6,218k	6,267k
Absolute poverty, before housing costs: pensioners	1,617k	1,550k	1,504k	1,517k	1,530k	1,539k	1,546k
Absolute poverty, after housing costs: everyone	14,840k	14,418k	14,804k	15,005k	15,265k	15,431k	15,663k
Absolute poverty, after housing costs: children	4,937k	4,609k	4,667k	4,687k	4,755k	4,820k	4,919k
Absolute poverty, after housing costs: working-age adults	8,401k	8,356k	8,734k	8,907k	9,048k	9,135k	9,257k
Absolute poverty, after housing costs: pensioners	1,503k	1,453k	1,404k	1,412k	1,461k	1,476k	1,487k
Relative poverty, before housing costs: everyone	11,890k	11,390k	11,463k	11,486k	11,426k	11,531k	11,707k
Relative poverty, before housing costs: children	3,915k	3,517k	3,517k	3,489k	3,449k	3,491k	3,549k
Relative poverty, before housing costs: working-age adults	6,197k	6,128k	6,335k	6,400k	6,388k	6,442k	6,537k
Relative poverty, before housing costs: pensioners	1,777k	1,744k	1,611k	1,597k	1,588k	1,598k	1,621k
Relative poverty, after housing costs: everyone	14,943k	14,586k	14,741k	14,809k	14,944k	15,039k	15,355k
Relative poverty, after housing costs: children	4,967k	4,674k	4,650k	4,630k	4,688k	4,712k	4,792k
Relative poverty, after housing costs: working-age adults	8,441k	8,448k	8,700k	8,836k	8,913k	8,976k	9,102k
Relative poverty, after housing costs: pensioners	1,535k	1,464k	1,391k	1,342k	1,343k	1,352k	1,460k

Inequality: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Gini coefficient, equivalised HBAI income before housing costs	0.3085	0.3058	0.3065	0.3071	0.3076	0.3082	0.3096

Mean household net income in each side's own deciles: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Decile 1: mean household_net_income per household	£17,769 †	£17,866 †	£17,838 †	£17,887 †	£18,174 †	£18,309 †	£18,446 †
Decile 2: mean household_net_income per household	£27,979 †	£28,847 †	£28,638 †	£28,880 †	£29,095 †	£29,614 †	£30,130 †
Decile 3: mean household_net_income per household	£34,362 †	£35,449 †	£35,981 †	£36,489 †	£36,760 †	£37,291 †	£38,112 †
Decile 4: mean household_net_income per household	£39,269 †	£40,695 †	£41,909 †	£42,378 †	£43,105 †	£43,923 †	£44,173 †
Decile 5: mean household_net_income per household	£43,314 †	£44,625 †	£45,559 †	£46,288 †	£47,354 †	£48,261 †	£49,593 †
Decile 6: mean household_net_income per household	£48,195 †	£49,500 †	£50,754 †	£51,500 †	£52,202 †	£53,162 †	£54,294 †
Decile 7: mean household_net_income per household	£56,164 †	£57,176 †	£57,763 †	£58,419 †	£58,909 †	£59,958 †	£61,826 †
Decile 8: mean household_net_income per household	£69,144 †	£70,966 †	£71,797 †	£73,236 †	£74,250 †	£75,671 †	£77,435 †
Decile 9: mean household_net_income per household	£79,644 †	£81,041 †	£82,857 †	£84,156 †	£85,561 †	£87,071 †	£89,924 †
Decile 10: mean household_net_income per household	£117,592 †	£120,304 †	£122,094 †	£124,173 †	£126,053 †	£128,344 †	£131,114 †

Standard reform costings (change in gov_balance): head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise basic rate by 1pp	£6.47bn	£6.76bn	£6.67bn	£6.86bn	£7.06bn	£7.29bn	£7.55bn
Raise higher rate by 1pp	£3.69bn	£3.98bn	£4.03bn	£4.24bn	£4.46bn	£4.73bn	£4.92bn
Raise personal allowance by ~800GBP/year	£-3.82bn	£-3.94bn	£-4.01bn	£-4.08bn	£-4.18bn	£-4.24bn	£-2.00bn
Raise child benefit by 25GBP/week per additional child	£-1.99bn	£-1.75bn	£-1.58bn	£-1.47bn	£-1.37bn	£-1.26bn	£-1.16bn
Reduce Universal Credit taper rate to 20%	£-20.40bn	£-20.95bn	£-21.38bn	£-21.63bn	£-21.88bn	£-22.23bn	£-22.62bn
Raise Class 1 main employee NICs rate to 10%	£11.02bn	£11.46bn	£11.77bn	£12.07bn	£12.41bn	£12.73bn	£13.10bn
Raise VAT standard rate by 2pp	£24.90bn	£25.56bn	£26.15bn	£26.76bn	£27.39bn	£28.04bn	£28.66bn
Raise additional rate by 3pp	£2.96bn	£3.21bn	£3.26bn	£3.46bn	£3.66bn	suppressed	suppressed
Raise the Universal Credit standard allowance by 10%	£-3.02bn	£-3.15bn	£-3.26bn	£-3.32bn	£-3.36bn	£-3.41bn	£-3.47bn
Raise the State Pension by 10%	£-7.78bn	£-8.01bn	£-8.02bn	£-8.12bn	£-8.37bn	£-8.53bn	£-8.87bn

Standard reforms: change in each reform's target: head levels

Measure (head)	2025-26	2026-27	2027-28	2028-29	2029-30	2030-31	2031-32
Raise basic rate by 1pp: change in income_tax	£6.61bn	£6.91bn	£6.83bn	£7.03bn	£7.24bn	£7.47bn	£7.73bn
Raise higher rate by 1pp: change in income_tax	£3.69bn	£3.99bn	£4.04bn	£4.25bn	£4.47bn	£4.74bn	£4.93bn
Raise personal allowance by ~800GBP/year: change in income_tax	£-3.95bn	£-4.08bn	£-4.17bn	£-4.24bn	£-4.34bn	£-4.41bn	£-1.76bn
Raise child benefit by 25GBP/week per additional child: change in child_benefit	£2.33bn	£2.14bn	£1.95bn	£1.84bn	£1.73bn	£1.62bn	£1.50bn
Reduce Universal Credit taper rate to 20%: change in universal_credit	£20.39bn	£20.95bn	£21.37bn	£21.62bn	£21.87bn	£22.22bn	£22.61bn
Raise Class 1 main employee NICs rate to 10%: change in national_insurance	£11.28bn	£11.74bn	£12.06bn	£12.37bn	£12.69bn	£13.03bn	£13.49bn
Raise VAT standard rate by 2pp: change in vat	£24.90bn	£25.56bn	£26.15bn	£26.76bn	£27.39bn	£28.04bn	£28.66bn
Raise additional rate by 3pp: change in income_tax	£2.96bn	£3.21bn	£3.26bn	£3.46bn	£3.66bn	suppressed	suppressed
Raise the Universal Credit standard allowance by 10%: change in universal_credit	£3.02bn	£3.15bn	£3.26bn	£3.32bn	£3.39bn	£3.44bn	£3.48bn
Raise the State Pension by 10%: change in state_pension	£10.68bn	£11.18bn	£11.31bn	£11.55bn	£12.00bn	£12.44bn	£12.94bn

[juaristi22]

Addressed all four findings from the review:

• Require both war_widows_pension_reported and widowed_parents_allowance_reported in the source observation before holding BSP flat. The projector, same-period fallback and economic-assumption reset use one canonical pair. Either column alone retains CPI.
• Track both input dependencies even when absent, while excluding calculated defaults and inputs supplied in different periods from the declaration.
• Update both published documentation pages, the dataset-source guide and BSP metadata. Correct the War Widow's Pension producer history and state the inherited-WPA residual understatement.

The guard regressions reproduced 12 failures before the fix. Tests now cover positive and zero complete pairs, both partial schemas, latest-observation provenance, the 4 × 4 reset matrix and branch invalidation for either input. Microcosm #1383 has merged and writes both required inputs unconditionally.

Rebased cleanly onto main at adbaa87d7. At head 72daf2817, the 12-file targeted manifest passes all 263 Python tests (282.13 seconds), the affected WPA policy file passes all 7 cases, and the documentation build passes. Independent fix verification is CLEAN for all four findings. Formatting and lint pass.

The class-level BSP CPI declaration remains in place for legacy datasets. No statutory rate or entitlement rule changes.

[vahid-ahmadi]

@juaristi22 thanks, this is my second review, at 72daf2817.

Round 1 findings

1. should, resolved. BSP is now held flat only when the source has both war_widows_pension_reported and widowed_parents_allowance_reported. BEREAVEMENT_SPLIT_INPUTS in economic_assumptions.py:132 is used in the projector (:351), the reset (:851) and the fallback in simulation.py:1395-1404. test_wpa_column_alone_preserves_legacy_cpi_uprating now expects CPI, for a positive and a zero allowance. I ran the head's test_bsp_dataset_projection.py against the round 1 code: 12 failed and 58 passed. The 12 are the partial-split, calculated-default and split-period cases, so the new tests catch the case I raised.
2. should, resolved. bereavement-support-plan.md now says what the code does and points to the guide. growthfactors.md:25-29 adds the exception under the CPI list.
3. nit, resolved. war_widows_pension.py:19-22 now credits microcosm#1333 and keeps policyengine-uk-data#578 for the Enhanced FRS.
4. nit, resolved. dataset-sources.md:139-142 and the bsp_reported docstring now say the frozen off-rate part understates an inherited additional pension.

New findings

None.

What I checked

• Rebase. The first commit is the same as the one I reviewed (git range-diff shows no change). The new commit touches only the BSP code, docs, changelog and tests. The branch merges cleanly with current main (1e98e09), and no commit on main since adbaa87d7 touches these files.
• Law, again. SI 2026/148 art 19 says each of £350, £3,500, £100 and £2,500 in reg 3 of SI 2017/410 "remains unchanged". The 2018 and 2020 orders use the same words. BSP is in the yearly review list in SSAA 1992 s 150(1)(q), but not among the sums that s 150(2)(a) and (3) require to rise with prices. Raising it is a choice, and each order has kept it flat. The docstring's "held unchanged by each up-rating order" is accurate.
• Producer. microcosm#1383 merged on 24 Oct and microcosm#1222 is closed. At its head e570d65ff both columns are in the person column lists of frs_spine.py and spi_spine.py, so Microcosm releases built from it meet the two-column rule. Older releases and the Enhanced FRS lack the allowance column and stay on CPI.
• Tests at the head: test_bsp_dataset_projection.py, test_projection_horizon.py, test_widowed_parents_allowance.py, test_war_widows_pension.py, test_uprating_inputs_reach_data.py, test_benefit_uprating_published.py and the code-health uprating, simulation-method, changelog, input-definition and spending tests: 261 passed. The WPA policy YAML: 7 passed. On main's model code the first two Reproducer tests fail (8 cases). The third, test_wpa_column_alone_preserves_legacy_cpi_uprating, passes there, as it should, because it guards the round 1 version, not the original bug.
• Aggregate impact on enhanced_frs_2024_25.h5 shows no flagged moves, as expected for a dataset without the split.
• Changelog. Dropping the leading - is right. towncrier adds the bullet itself, which is why several entries in CHANGELOG.md read - - .

I did not run the full suite or build a Microcosm dataset with #1383, and I did not read the unchanged parts of the docs pages again.

Verdict. All four round 1 findings are resolved and I found nothing new. CI is green at this head, including all five Python shards and Aggregate impact. From my side this is ready to merge.

🤖 Generated with Claude Code

[vahid-ahmadi]

Approving at 72daf28; see the round 2 comment above.

🤖 Generated with Claude Code