Calibrate salary sacrifice population to HMRC/ASHE headcount targets#268
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vahid-ahmadi merged 4 commits intomainfrom Feb 16, 2026
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Calibrate salary sacrifice population to HMRC/ASHE headcount targets#268vahid-ahmadi merged 4 commits intomainfrom
vahid-ahmadi merged 4 commits intomainfrom
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Add two-stage imputation: QRF for non-respondents, then headcount-targeted conversion of pension contributors to below-cap SS users. Add three new calibration targets in loss.py (7.7mn total, 3.3mn above cap, 4.3mn below). Source: https://www.gov.uk/government/publications/salary-sacrifice-reform-for-pension-contributions-effective-from-6-april-2029 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Tests total (7.7mn), below-cap (4.3mn), and above-cap (3.3mn) SS user counts. Marked xfail until recalibration. Skipped when enhanced FRS dataset is not available. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Fixes ModuleNotFoundError in CI where setuptools is not installed. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Resolve conflict in utils/loss.py (keep registry delegation). Incorporate salary sacrifice headcount targets from PR #268 into the structured registry (obr.py, compute/income.py, build_loss_matrix.py). Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Feb 17, 2026
PR #268 added Stage 2 imputation (records at exactly 2k) and headcount calibration targets. The calibrator classified above/below 2k at uprated 2025 prices, but the saved h5 stores 2023 prices where the classification differs (8.55% inflation flips boundary records). Now evaluates SS at base-year prices before thresholding so calibration matches end-user values. Also reduces Stage 2 target to 3M so the calibrator upweights gently rather than overshooting. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
salary_sacrifice.py: converts pension contributors without SS into below-cap (≤£2,000) SS users, moving employee pension contributions to salary sacrifice to keep totals consistentloss.py: total SS users (7.7mn), below-cap (4.3mn), above-cap (3.3mn), anchored at ASHE 2024 with 2.4%/year growth (OBR para 1.7)Context
PE currently undercounts salary sacrifice users (4.5mn vs 7.7mn HMRC estimate). The gap is almost entirely in below-cap contributors — auto-enrolment workers who don't realise their pension is via salary sacrifice. The existing calibration targets only cover monetary amounts (£24bn contributions, tax relief by band) with no headcount constraint.
Test plan
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