`cmbtp` value

[bodiyang]

Issue:

The output variable cmbtp (estimate of income on AMT Form 6251 but not in AGI) is showing a highly wavering range, from Minimum -23842830 to Maximum 83355100, with expected aggregate SUM 4308354591.

cmbtp matches with line 3 of the form 6251

Would this bring us concerns? ~ because a skewed cmbtp value might lead to consequences in the AMT liability calculation.

[bodiyang]

Analysis:

The "wavering" cmbtp variable will not have consequence on the AMT liability calculation. The possible consequence we may have is the aggregate value of cmbtp itself.

cmbtp is calculated in finalprep.py, cmbtp_standard = e62100 (AMT taxable income) - e00100 (AGI) + e00700 (Taxable refunds of state and local income taxes)

e62100, the AMT taxable income, a variable in PUF, is a blow-up factor in Tax-Data's extrapolation process. So the aggregate of AMT taxable income can be guaranteed. cmbtp, on the other hand, is essentially an intermediated variable, in Tax-Data. cmbpt is dependent upon the AMT taxable income, not the other way around.

So the only possible consequence from a skewed cmbtp is the aggregate of itself. If we care about cmbtp, a solution is to find if there any tax statistics (from SOI estimate, etc.) about this variable, and bring it in as a target in Tax-Data.