Carer's Allowance earnings hard-code the one-half pension contribution deduction #2517

carers_allowance_earnings deducts a literal one-half of pension contributions (policyengine_uk/variables/gov/dwp/carers_allowance_earnings.py:122):

half_pension_contributions = 0.5 * person("pension_contributions", period)

The share can't be reformed, and nothing ties it to the law. #2516 fixes the same kind of literal for Council Tax Reduction and Income Support, and #2497 for Housing Benefit. JSA's literal is tracked in #140.

What the law says. The Carer's Allowance earnings limit counts net earnings under the Social Security Benefit (Computation of Earnings) Regulations 1996 (SI 1996/2745), in force from 25 November 1996:

• employed earners: reg. 10(4)(b) deducts "one half" of any sum the claimant pays as a contribution towards an occupational or personal pension scheme;
• self-employed earners: regs. 13(1)(b)(ii), 13(4)(c) and 13(10)(b) deduct "one half" of any premium paid for a retirement annuity contract or a personal pension scheme.

The text is the same as made and today, and legislation.gov.uk records no amendment to these paragraphs. Northern Ireland's Social Security Benefit (Computation of Earnings) Regulations (Northern Ireland) 1996 (SR 1996/520) use the same words in the same paragraphs, from the same date.

Fix. Add gov.dwp.carers_allowance.pension_contribution_deduction_rate (0.5 from 1996-11-25), citing those provisions, and read it in place of the literal. Current-law outputs stay the same.