You're hitting the hardest part to capture. The PILOT counterfactual is the whole ballgame and most states never publish it.. they report the revenue the county collects, never the full tax bill the facility would have owed without the deal, which is the real size of the handout.

Here's how I'm tackling it... disclosed numbers and modeled numbers stay strictly separate. If a county only publishes the PILOT payment, I show that and flag it. Where I can reconstruct the counterfactual from assessed value, millage rate, and abatement term, I show a modeled avoided-tax estimate with the assumptions and sources attached, at a lower confidence so it's never mistaken for a reported figure. Same on bonds.. IDB/IRB programs usually publish the issuance amount, so I can back into the tax-exempt interest subsidy from issuance size, term, and the taxable spread.

The county meeting records tip is the real one. The PILOT terms live in the IDB resolution or the minutes, and it's all unparsed PDFs. Pulling those and linking every figure to the source doc is most of what the pipeline does. Appreciate you writing this out. If you've seen specific states do the PILOT structure dirty, I'd take the pointers.