Why do we estimate repealing head of household status raises ~1/2 of CBO?

[MaxGhenis]

We estimate roughly half the impact of repealing head of household filing status, compared to CBO/JCT's 2018 report.

Model	Amount ($ billions, 2023)
CBO	18.5
PE CPS	9.4
PE Enhanced CPS	8.8

The reform is simple, and appears to work correctly for individual households, lowering net income of a single parent and having no effect on either a single person without children or a joint filer with children.

[MaxGhenis]

Updated for 2024 with policyengine-us version 0.708.4:

Model	Amount ($ billions, 2024)
CBO	19.3
PE CPS	9.4
PE Enhanced CPS	9.0

Improving surviving spouse filing logic (#4095) should have raised the impact of Hoh, but other changes since December may have gone the other direction. Next step is calibrating to returns by filing status (#4093).

[MaxGhenis]

Calibrating by filing status got the ECPS much closer; here are numbers for policyengine-us 0.710.1:

Model	Amount ($ billions, 2024)
CBO	19.3
PE CPS	8.2
PE Enhanced CPS	22.1