Summary Statistics and Findings using CCAO’s PTAXSIM package
Bonus research summarized for the public by the GFRC RAs
Background Information
All data was originally posted by the Cook County Assessor’s Office (CCAO).
Tax data for Cook County was gathered using CCAO’s ptaxsim package and corresponding database.
All summarizing of data was done by Research Assistants working for the Government Finance Research Center at the University of Illinois Chicago.
If ignoring TIFs, the residential share of EAV is:
\[ ResidentrialShare = \frac{TaxableEAV_{residential} - ExemptEAV_{residential}} {TaxableEAV} \]
\[ ResidentialShare = \frac{1-\lambda}{1-\lambda-\psi} \]
\[ TaxableBase = AV_{equalized} - TIFincrement - EAV_{exempt} \]
\[ TIFincrement = AV_{equalized} - EAV_{frozen} \]
The aggregate, or composite, tax rate is the sum of the individual taxing agency tax rates, or \(\sum(rate_{agency})\), for all taxing agencies that tax a location. Each unique combination of taxing agencies is assigned a tax code by the assessor’s office.