Validate PolicyEngine child poverty estimates against RF/OBR benchmarks

Summary

The Resolution Foundation and OBR have published specific child poverty estimates for the November 2025 Autumn Budget. We should validate PolicyEngine's estimates against these benchmarks.

Target Benchmarks

Two-Child Limit Removal

Baseline Child Poverty

Methodology Differences to Consider

1. Nowcasting: RF uses FRS with ONS price index nowcasting
2. Earnings growth: RF uses Bank of England/OBR wage forecasts with spillover effects
3. Housing costs: RF uses ONS PIPR for rent inflation
4. Take-up assumptions: Different benefit take-up rate assumptions

Tasks

• Run PolicyEngine simulation for two-child limit removal
• Compare fiscal cost estimates with OBR Table 3.2
• Compare child poverty reduction with RF/OBR estimates
• Document any significant discrepancies and their likely causes
• Update documentation if methodology adjustments are needed

Related Issues

• #1171 - PE vs RF nowcasting documentation
• #1179 - RF earnings growth methodology
• #1388 - Two-child limit removal implementation

Source

• Resolution Foundation "No half measures": https://www.resolutionfoundation.org/publications/no-half-measures/
• OBR EFO November 2025, Chapter 3

🤖 Generated with Claude Code

Start by running the PolicyEngine simulation for two-child limit removal and reviewing related issue #1388. Compare the results with OBR Table 3.2 and the Resolution Foundation benchmarks, accounting for the listed nowcasting, earnings-growth, housing-cost, and take-up differences. Done means documenting discrepancies and updating methodology documentation if adjustments are needed.