PolicyEngine / PolicyEngine/policyengine-uk

WTC 30-hour element is CPI-uprated instead of using the 2024-25 rate

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Dominant language
Python
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50
Forks
33
Avg merge
20h 58m
Merged PRs (30d)
14

Description

Problem

policyengine_uk/parameters/gov/dwp/tax_credits/working_tax_credit/elements/worker.yaml stops at 2021-04-06: 830 and relies on gov.benefit_uprating_cpi. That makes the 2024-25 Working Tax Credit 30-hour element evaluate to about GBP 1,010.22 in PE-UK.

Official HMRC/legislation sources give GBP 1,015 for the 2024-25 30-hour element:

Expected

The 2024-25 WTC 30-hour element should match the official GBP 1,015 rate. A likely fix is to add an explicit 2024-25 value to the worker element parameter, but the broader WTC parameter handling after tax credits ended on 5 April 2025 should also be audited before changing future-year behavior.

Context

This surfaced while adding Axiom RuleSpec coverage for UKSI 2002/2005 Schedule 2. The Axiom oracle mapping is treating this specific output as known-not-comparable until PE-UK is fixed.

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First steps

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  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with policyengine_uk/parameters/gov/dwp/tax_credits/working_tax_credit/elements/worker.yaml and compare its dated values with the HMRC manual, Spring Budget Annex A, and the 2024-04-06 regulations. Review the surrounding Working Tax Credit parameter handling and the Axiom RuleSpec coverage that exposed the mismatch. Done means the 2024-25 30-hour element matches GBP 1,015 and future-year behavior is checked against the tax-credit end date.

Written by the indexing model from the issue text.

Assessment

Tech stack
yaml
Domain
backend
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
68/100

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