From 68edefe43262e30169a373d64ed9c08a49a23b64 Mon Sep 17 00:00:00 2001 From: Max Ghenis Date: Mon, 26 Oct 2026 10:50:46 -0700 Subject: [PATCH 1/5] Point the two-child limit validation page at Scorecard's rows The page hard-coded PolicyEngine's estimates beside the DWP, HM Treasury and Resolution Foundation figures. Scorecard now holds that comparison, recomputed on a certified release with a status and notes per row (PolicyEngine/policyengine-scorecard#225). The page keeps the method: the reform, the measures and variables, and a snippet. Co-Authored-By: Claude Opus 5.5 --- changelog.d/1398.changed.md | 1 + docs/book/validation/child-poverty-tcl.md | 226 ++++++++---------- .../reform-impacts-dashboard-plan.md | 7 +- 3 files changed, 105 insertions(+), 129 deletions(-) create mode 100644 changelog.d/1398.changed.md diff --git a/changelog.d/1398.changed.md b/changelog.d/1398.changed.md new file mode 100644 index 0000000000..bfbb1e03a8 --- /dev/null +++ b/changelog.d/1398.changed.md @@ -0,0 +1 @@ +Moved the two-child limit child-poverty comparison from the validation page to PolicyEngine Scorecard, which recomputes it on a certified release; the page now documents the method and links to each Scorecard row. diff --git a/docs/book/validation/child-poverty-tcl.md b/docs/book/validation/child-poverty-tcl.md index 5df7cd02f3..170dc13f6a 100644 --- a/docs/book/validation/child-poverty-tcl.md +++ b/docs/book/validation/child-poverty-tcl.md @@ -1,146 +1,120 @@ -# Child poverty validation: removing the two-child limit (2029-30) +# Child poverty validation: removing the two-child limit -This page compares PolicyEngine UK's estimate of the child-poverty -impact and fiscal cost of removing the [Universal Credit two-child -limit][gov-2cl] against the published estimates from the Department for -Work and Pensions, the Office for Budget Responsibility and the Resolution -Foundation. Budget 2025 announced the removal with effect from 6 April -2026, which the -`gov.dwp.universal_credit.elements.child.limit.child_count` parameter -encodes (`.inf` from `2026-04-06`). +This page sets out how PolicyEngine UK estimates the child-poverty impact +and fiscal cost of removing the [Universal Credit two-child +limit][gov-2cl], which Budget 2025 announced from 6 April 2026. The +comparison with the published estimates from the Department for Work and +Pensions, HM Treasury and the Resolution Foundation is in [PolicyEngine +Scorecard][scorecard-lane]. Scorecard computes PolicyEngine's figures on a +certified release, states for every row whether the two concepts match, +and keeps the earlier runs in each row's history. Tracks [#1398](https://github.com/PolicyEngine/policyengine-uk/issues/1398). -## Results - -| Source | Children lifted from relative low income (2029-30) | Treasury cost (2029-30) | -|--------|----------------------------------------:|------------------------:| -| [DWP poverty impact assessment][gov-2cl] (children); [Budget 2025, Table 1.2][budget-2025] (cost, OBR-certified) | 450,000 (AHC); 300,000 (BHC) | £3.1 bn | -| [Resolution Foundation *No half measures*][rf-nhm] | 480,000 (AHC) | £3.5 bn | -| **PolicyEngine UK, Microcosm UK 2024-25 (AHC)** | **~548,000** | **£3.21 bn** | -| **PolicyEngine UK, Microcosm UK 2024-25 (BHC)** | **~460,000** | (same) | - -All the figures are relative low income: below 60% of the contemporary -median. The PolicyEngine rows count HBAI dependent children -(`is_hbai_dependent_child`), as DWP does, and were run on 23 October 2026 -on policyengine-uk 2.148.3 (main at `c65bced64`) with the certified -Microcosm UK 2024-25 national release (`microcosm-uk-2024-25-national-20261019T083323Z-6cba5d71`, SHA-256 -`810ba980…`). On that run PolicyEngine's headcounts are above DWP's and the -Resolution Foundation's, and its cost sits between the Budget 2025 and -Resolution Foundation figures. - -On absolute low income the same run lifts ~549,000 children after housing -costs and ~325,000 before, against DWP's 250,000 on both measures (Tables 3 -and 4). These are not like for like: PolicyEngine's absolute line is -60% of the FYE 2025 median held constant in real terms, the reference year -HBAI adopted in March 2026, while DWP's note predates that change and cites -the FYE 2024 HBAI methodology, whose line is 60% of the FYE 2011 median. - -Earlier versions of this page reported ~463,000 (AHC) and ~336,000 (BHC) -children and £3.26 bn on an earlier Microcosm UK release (SHA-256 -`aa31bdf6…`, policyengine-uk 2.123.7), and ~501,000, ~415,000 and £3.40 bn -on the Enhanced FRS 2022-23 in May 2026. The snippet those versions showed -computed only the after-housing-costs figure, using `in_poverty_ahc` -(absolute low income) and counting children with `is_child` (everyone under -18), so at least those figures are not comparable with the relative -benchmarks above; the code for the before-housing-costs figures was not -shown. - -## How the estimate was produced +## The comparison in Scorecard + +| Benchmark | Scorecard row | +|---|---| +| DWP: children in relative low income, after housing costs, FYE 2030 (Table 1) | [row][dwp-rel-ahc] | +| DWP: children in relative low income, before housing costs, FYE 2030 (Table 2) | [row][dwp-rel-bhc] | +| DWP: children in absolute low income, after housing costs, FYE 2030 (Table 3) | [row][dwp-abs-ahc] | +| DWP: children in absolute low income, before housing costs, FYE 2030 (Table 4) | [row][dwp-abs-bhc] | +| DWP: children in gaining households, FYE 2030 | [row][dwp-gainers] | +| HM Treasury: static Exchequer cost, 2029-30 | [row][hmt-static] | +| HM Treasury: post-behavioural cost, 2029-30 (the £3.1 billion in Budget 2025 Table 1.2) | [row][hmt-post] | +| Resolution Foundation, *No half measures*: children, 2029-30 | [row][rf-children] | +| Resolution Foundation, *No half measures*: cost, 2029-30 | [row][rf-cost] | + +Each row shows the published figure, PolicyEngine's value, the comparison +status and the notes that explain it. Two notes matter most: + +- **The absolute line.** DWP's note uses the FYE 2011 reference year (60% + of the FYE 2011 median, held constant in real terms). PolicyEngine UK + serves the FYE 2025 reference, so Scorecard also constructs the FYE 2011 + line for that comparison. +- **Static and post-behavioural costs.** PolicyEngine's cost is static, so + it compares with HM Treasury's static leg. The £3.1 billion includes a + behavioural adjustment. + +Scorecard also records a [decomposition][decomposition] of how the +estimate moved between PolicyEngine's September and October 2026 figures: +how much came from the data, the model version, the child count and the +relative-line convention. + +## The reform + +The `gov.dwp.universal_credit.elements.child.limit.child_count` parameter +is 2 from 6 April 2017 and infinite from 6 April 2026. Current law already +removes the limit, so the estimate compares two worlds: current law, and +current law with the parameter set back to 2. The effect of removing the +limit is current law minus that with-limit world. A year `Y` in +PolicyEngine UK is the financial year that starts in April `Y`, so FYE +2030 is `2029`. + +## The measures + +- **Relative low income**: `in_relative_poverty_ahc` and + `in_relative_poverty_bhc`. These flag equivalised HBAI household income + below 60% of the median of the world being calculated, with the median + taken over people. +- **Absolute low income**: `in_poverty_ahc` and `in_poverty_bhc`. These use + 60% of the FYE 2025 median, held constant in real terms. +- **Children**: `is_hbai_dependent_child`, HBAI's dependent children, as + DWP counts them. +- **Cost**: the change in `gov_balance` (tax less spending). The estimate + is static: no behavioural response runs, and `would_claim_uc` is a data + input, so take-up does not respond to the reform. ```python -from policyengine_uk import Microsimulation - -# Local path to the Microcosm UK 2024-25 national release file. -DATASET = "microcosm_uk_2024_25.h5" -YEAR = 2029 # fiscal year 2029-30 - -# Current law baseline (TCL removed from 2026-04-06 per Budget 2025) -sim_baseline = Microsimulation(dataset=DATASET) - -# Counterfactual where the TCL is held in place at 2 children -sim_counter = Microsimulation( - dataset=DATASET, - reform={ - "gov.dwp.universal_credit.elements.child.limit.child_count": { - f"{YEAR}-01-01": 2, - }, - }, -) +import policyengine as pe -# HBAI dependent children, as in DWP's statistics. -is_child = sim_baseline.calculate("is_hbai_dependent_child", YEAR) +YEAR = 2029 # FY 2029-30 (FYE 2030) +LIMIT = "gov.dwp.universal_credit.elements.child.limit.child_count" -for measure in ["in_relative_poverty_ahc", "in_relative_poverty_bhc"]: - baseline = sim_baseline.calculate(measure, YEAR, map_to="person") - counter = sim_counter.calculate(measure, YEAR, map_to="person") - lifted = ((counter.astype(float) - baseline.astype(float)) * is_child).sum() - print(f"{measure} children lifted: {lifted / 1e3:.0f}k") +current_law = pe.uk.managed_microsimulation() +with_limit = pe.uk.managed_microsimulation( + reform={LIMIT: {"2025-01-01.2035-12-31": 2}} +) -fiscal_cost = ( - sim_counter.calculate("gov_balance", YEAR).sum() - - sim_baseline.calculate("gov_balance", YEAR).sum() +children = current_law.calculate("is_hbai_dependent_child", YEAR) +for measure in ("in_relative_poverty_ahc", "in_relative_poverty_bhc"): + lifted = ( + with_limit.calculate(measure, YEAR, map_to="person").astype(float) + - current_law.calculate(measure, YEAR, map_to="person").astype(float) + ) * children + print(measure, lifted.sum()) + +cost = ( + with_limit.calculate("gov_balance", YEAR).sum() + - current_law.calculate("gov_balance", YEAR).sum() ) -print(f"Treasury cost: £{fiscal_cost / 1e9:.2f}bn") +print("cost", cost) ``` -This is a *reverse* comparison: PolicyEngine's baseline already includes -the TCL removal (the parameter flips to infinity from 2026-04-06), so the -counterfactual *re-imposes* the limit at 2 children to compute the -2029-30 effect. The signs cancel out: the children-lifted figure is -positive (baseline has fewer in poverty than counterfactual) and the -Treasury cost is positive (the baseline pays more Universal Credit, so its -`gov_balance`, tax less spending, is lower than the counterfactual's). - -## Why the estimates differ - -Three plausible drivers of the remaining differences: - -1. **Nowcasting methodology**. RF projects incomes with its own nowcast, - with private rents rising in line with average earnings after a - 12-month lag and its own after-housing-costs deflator; DWP uses its - static Policy Simulation Model on the FRS for FYE 2022 to 2024 with its - caseload forecasts. See the - [PolicyEngine vs RF comparison](../assumptions/nowcasting-comparison.md) - and the [RF methodology detail](../assumptions/rf-nowcasting-methodology.md) - for where PolicyEngine's nowcasting differs from RF's. -2. **Take-up assumptions**. PolicyEngine decides Universal Credit claims - with flags set in the data, which do not respond to the reform: a family - claims if `would_claim_uc` is true, or if DWP has moved it off a closed - legacy benefit it reports (tax credits, Income Support or income-based - Jobseeker's Allowance; `legacy_benefits_closed`, which leaves out - families sent to Pension Credit instead) and - `would_claim_uc_at_legacy_closure` is true. - The data set `would_claim_uc` for every family that reports Universal - Credit and draw it at a residual rate for the rest, so newly entitled - families claim at that residual rate unless they reported a closed - legacy benefit. A - source that assumes lower take-up among newly entitled families would - show a smaller headcount and cost. -3. **Data and calibration vintage**. The DWP and OBR estimates were - finalised against the OBR's November 2025 forecast, and RF's - (30 October 2025) against the OBR's March 2025 earnings forecast and the - Bank of England's August 2025 inflation forecast; PolicyEngine's - parameters tick over with each EFO release. The Microcosm release is - built from FRS 2024-25, with take-up anchored on reported receipt. - -## How to keep this validation alive - -- Re-run the snippet on each new Microcosm UK release, and when the - remaining `would_claim_*` conversions (#1621) land. Both could move the - AHC poverty rate by a non-trivial amount. -- After each new EFO release, update the per-year poverty headcounts and - the fiscal cost table. +`pe.uk.managed_microsimulation()` loads the data release that +policyengine.py certifies with the installed model version. Scorecard's +[`compute_uk_two_child_limit_poverty.py`][compute] runs the same +comparison for every year, measure and group the benchmarks use. ## References -- HM Treasury, [Budget 2025][budget-2025], Table 1.2: the OBR-certified cost of removing the two-child limit (£3.1 billion in 2029-30). -- OBR, [Economic and Fiscal Outlook November 2025][obr-efo]. +- DWP, [Removing the two-child limit on Universal Credit: impact on low income poverty levels in the United Kingdom][gov-2cl] (26 November 2025), Tables 1 to 4. +- HM Treasury, [Budget 2025][budget-2025], Table 1.2. - Resolution Foundation, [No half measures: setting child poverty on a downward course at the Autumn Budget][rf-nhm] (30 October 2025). -- DWP, [Removing the two-child limit on Universal Credit: impact on low income poverty levels in the United Kingdom][gov-2cl], Tables 1 and 2 (relative low income) and 3 and 4 (absolute low income), financial year ending 2030. - Issue: [#1398](https://github.com/PolicyEngine/policyengine-uk/issues/1398). Related: [#1171](https://github.com/PolicyEngine/policyengine-uk/issues/1171), [#1388](https://github.com/PolicyEngine/policyengine-uk/issues/1388). -[obr-efo]: https://obr.uk/efo/economic-and-fiscal-outlook-november-2025/ +[gov-2cl]: https://www.gov.uk/government/publications/poverty-impacts-of-social-security-changes-at-budget-2025/removing-the-two-child-limit-on-universal-credit-impact-on-low-income-poverty-levels-in-the-united-kingdom [budget-2025]: https://www.gov.uk/government/publications/budget-2025-document/budget-2025-html [rf-nhm]: https://www.resolutionfoundation.org/publications/no-half-measures/ -[gov-2cl]: https://www.gov.uk/government/publications/poverty-impacts-of-social-security-changes-at-budget-2025/removing-the-two-child-limit-on-universal-credit-impact-on-low-income-poverty-levels-in-the-united-kingdom +[scorecard-lane]: https://www.policyengine.org/scorecard/?country=uk&view=validation +[dwp-rel-ahc]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=2f90d6562b5cf8008c94 +[dwp-rel-bhc]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=d840d48b5aa86092e053 +[dwp-abs-ahc]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=0953bfed29bf91c21076 +[dwp-abs-bhc]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=f0db70b0fc559137b2b8 +[dwp-gainers]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=c95c29a868535490a0e4 +[hmt-static]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=67f3e4d6a1070d902798 +[hmt-post]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=97d6c677b464338f8233 +[rf-children]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=5cd40f11fde6cd6df668 +[rf-cost]: https://www.policyengine.org/scorecard/?country=uk&view=validation&claim=a05d61066f4bc096db86 +[decomposition]: https://github.com/PolicyEngine/policyengine-scorecard/blob/main/results/uk/two_child_limit_poverty/DECOMPOSITION.md +[compute]: https://github.com/PolicyEngine/policyengine-scorecard/blob/main/pipeline/compute_uk_two_child_limit_poverty.py diff --git a/docs/book/validation/reform-impacts-dashboard-plan.md b/docs/book/validation/reform-impacts-dashboard-plan.md index 529b198808..c66b178c0e 100644 --- a/docs/book/validation/reform-impacts-dashboard-plan.md +++ b/docs/book/validation/reform-impacts-dashboard-plan.md @@ -167,8 +167,9 @@ Add to v2 over time as published OBR / RF reforms become available benchmarks: - Reinstate the two-child limit. The baseline removes it from 6 April - 2026, and [child-poverty-tcl.md](child-poverty-tcl.md) compares its - removal with the DWP, Budget 2025 and Resolution Foundation estimates. + 2026, and [child-poverty-tcl.md](child-poverty-tcl.md) links to + Scorecard's comparison of its removal with the DWP, HM Treasury and + Resolution Foundation estimates. - Freeze the Personal Allowance for an additional year (to 2031-32, so it needs a later reference year than 2029). - 1pp employer NI change. @@ -197,7 +198,7 @@ relevant pages are: - [nowcasting-comparison.md](../assumptions/nowcasting-comparison.md) (PolicyEngine vs RF). - [rf-nowcasting-methodology.md](../assumptions/rf-nowcasting-methodology.md) (RF methodology detail). -- [child-poverty-tcl.md](child-poverty-tcl.md) (the child-poverty impact and cost of removing the two-child limit, against DWP, Budget 2025 and Resolution Foundation estimates). +- [child-poverty-tcl.md](child-poverty-tcl.md) (how PolicyEngine UK estimates the child-poverty impact and cost of removing the two-child limit, with links to Scorecard's comparison against DWP, HM Treasury and Resolution Foundation estimates). ## Open questions From fe6a92b83a109ba28b6c13cb6893b6ff1606b77e Mon Sep 17 00:00:00 2001 From: Max Ghenis Date: Mon, 26 Oct 2026 11:37:57 -0700 Subject: [PATCH 2/5] Say the Scorecard decomposition names the releases that moved the estimate Co-Authored-By: Claude Opus 5.5 --- docs/book/validation/child-poverty-tcl.md | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/book/validation/child-poverty-tcl.md b/docs/book/validation/child-poverty-tcl.md index 170dc13f6a..38c57b6061 100644 --- a/docs/book/validation/child-poverty-tcl.md +++ b/docs/book/validation/child-poverty-tcl.md @@ -39,7 +39,7 @@ status and the notes that explain it. Two notes matter most: Scorecard also records a [decomposition][decomposition] of how the estimate moved between PolicyEngine's September and October 2026 figures: how much came from the data, the model version, the child count and the -relative-line convention. +relative-line convention, and which policyengine-uk releases moved it. ## The reform From fdde31762cbb8af123e2512691662bf4d533fe6d Mon Sep 17 00:00:00 2001 From: Max Ghenis Date: Mon, 26 Oct 2026 13:26:59 -0700 Subject: [PATCH 3/5] Format the validation page's code block with the pinned ruff Co-Authored-By: Claude Opus 5.5 --- docs/book/validation/child-poverty-tcl.md | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/docs/book/validation/child-poverty-tcl.md b/docs/book/validation/child-poverty-tcl.md index 38c57b6061..49837ce189 100644 --- a/docs/book/validation/child-poverty-tcl.md +++ b/docs/book/validation/child-poverty-tcl.md @@ -72,9 +72,7 @@ YEAR = 2029 # FY 2029-30 (FYE 2030) LIMIT = "gov.dwp.universal_credit.elements.child.limit.child_count" current_law = pe.uk.managed_microsimulation() -with_limit = pe.uk.managed_microsimulation( - reform={LIMIT: {"2025-01-01.2035-12-31": 2}} -) +with_limit = pe.uk.managed_microsimulation(reform={LIMIT: {"2025-01-01.2035-12-31": 2}}) children = current_law.calculate("is_hbai_dependent_child", YEAR) for measure in ("in_relative_poverty_ahc", "in_relative_poverty_bhc"): From 6b98161832287c9ae5217020223d08c78b44dc0d Mon Sep 17 00:00:00 2001 From: Max Ghenis Date: Mon, 26 Oct 2026 13:28:16 -0700 Subject: [PATCH 4/5] Name policyengine-uk's FYE 2011 absolute line on the validation page policyengine-uk 2.155.0 added in_absolute_poverty_fye2011_ahc and _bhc. Scorecard's certified release predates them, so it still constructs the line. Co-Authored-By: Claude Opus 5.5 --- docs/book/validation/child-poverty-tcl.md | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/docs/book/validation/child-poverty-tcl.md b/docs/book/validation/child-poverty-tcl.md index 49837ce189..07dbc67b3c 100644 --- a/docs/book/validation/child-poverty-tcl.md +++ b/docs/book/validation/child-poverty-tcl.md @@ -29,9 +29,11 @@ Each row shows the published figure, PolicyEngine's value, the comparison status and the notes that explain it. Two notes matter most: - **The absolute line.** DWP's note uses the FYE 2011 reference year (60% - of the FYE 2011 median, held constant in real terms). PolicyEngine UK - serves the FYE 2025 reference, so Scorecard also constructs the FYE 2011 - line for that comparison. + of the FYE 2011 median, held constant in real terms). PolicyEngine UK's + `in_poverty_*` use the FYE 2025 reference. The FYE 2011 line is + `in_absolute_poverty_fye2011_*` from policyengine-uk 2.155.0. The + certified release Scorecard runs on predates that, so Scorecard + constructs the FYE 2011 line for the comparison. - **Static and post-behavioural costs.** PolicyEngine's cost is static, so it compares with HM Treasury's static leg. The £3.1 billion includes a behavioural adjustment. @@ -57,8 +59,10 @@ PolicyEngine UK is the financial year that starts in April `Y`, so FYE `in_relative_poverty_bhc`. These flag equivalised HBAI household income below 60% of the median of the world being calculated, with the median taken over people. -- **Absolute low income**: `in_poverty_ahc` and `in_poverty_bhc`. These use - 60% of the FYE 2025 median, held constant in real terms. +- **Absolute low income**: `in_poverty_ahc` and `in_poverty_bhc`. From FYE + 2022 these use 60% of the FYE 2025 median, held constant in real terms. + `in_absolute_poverty_fye2011_ahc` and `in_absolute_poverty_fye2011_bhc` + use the FYE 2011 median in every year, the line in DWP's note. - **Children**: `is_hbai_dependent_child`, HBAI's dependent children, as DWP counts them. - **Cost**: the change in `gov_balance` (tax less spending). The estimate From a75c57b954cfcd85ba321e370554a29cf5ef5ae5 Mon Sep 17 00:00:00 2001 From: Max Ghenis Date: Wed, 28 Oct 2026 00:28:20 -0400 Subject: [PATCH 5/5] Address review: dedicated issue, full-rollout backlink, certified pair, static scope Fixes #2704. The changelog fragment now carries #2704, the issue this PR closes. #1398 stays open. two-child-limit-full-rollout.md now describes what the TCL page holds. The snippet note names policyengine.py 6.11.0's pinned policyengine-uk 2.132.6. The static note says the labour-supply elasticities are zero, not that no behavioural response runs. Co-Authored-By: Claude Opus 5.5 --- changelog.d/{1398.changed.md => 2704.changed.md} | 0 docs/book/validation/child-poverty-tcl.md | 10 ++++++---- docs/book/validation/two-child-limit-full-rollout.md | 4 +++- 3 files changed, 9 insertions(+), 5 deletions(-) rename changelog.d/{1398.changed.md => 2704.changed.md} (100%) diff --git a/changelog.d/1398.changed.md b/changelog.d/2704.changed.md similarity index 100% rename from changelog.d/1398.changed.md rename to changelog.d/2704.changed.md diff --git a/docs/book/validation/child-poverty-tcl.md b/docs/book/validation/child-poverty-tcl.md index 07dbc67b3c..ea6a8f886b 100644 --- a/docs/book/validation/child-poverty-tcl.md +++ b/docs/book/validation/child-poverty-tcl.md @@ -66,8 +66,8 @@ PolicyEngine UK is the financial year that starts in April `Y`, so FYE - **Children**: `is_hbai_dependent_child`, HBAI's dependent children, as DWP counts them. - **Cost**: the change in `gov_balance` (tax less spending). The estimate - is static: no behavioural response runs, and `would_claim_uc` is a data - input, so take-up does not respond to the reform. + is static: the labour-supply elasticities are zero, and `would_claim_uc` + is a data input, so neither work nor take-up responds to the reform. ```python import policyengine as pe @@ -93,8 +93,10 @@ cost = ( print("cost", cost) ``` -`pe.uk.managed_microsimulation()` loads the data release that -policyengine.py certifies with the installed model version. Scorecard's +`pe.uk.managed_microsimulation()` loads the dataset pinned by the +installed policyengine.py release. Each release certifies that dataset +with one policyengine-uk version, which `policyengine[uk]` installs: +6.11.0, the release Scorecard uses, pins policyengine-uk 2.132.6. Scorecard's [`compute_uk_two_child_limit_poverty.py`][compute] runs the same comparison for every year, measure and group the benchmarks use. diff --git a/docs/book/validation/two-child-limit-full-rollout.md b/docs/book/validation/two-child-limit-full-rollout.md index f2575465d5..7e274ca3c1 100644 --- a/docs/book/validation/two-child-limit-full-rollout.md +++ b/docs/book/validation/two-child-limit-full-rollout.md @@ -4,7 +4,9 @@ This page shows how to reproduce published estimates of reforming the Universal Credit two-child limit that assume the limit is **fully rolled out**, such as the IFS Green Budget 2025 comment [Options for reforming the two-child limit][ifs-2025], and how PolicyEngine UK's results compare. For -the 2029-30 comparison with DWP, OBR and Resolution Foundation estimates, see +how PolicyEngine UK estimates removing the limit in 2029-30, with links to +Scorecard's comparison against DWP, HM Treasury and Resolution Foundation +estimates, see [Child poverty validation: removing the two-child limit](child-poverty-tcl.md). ## Settings that matter