35 ILCS 200/4-20
Any assessor in counties with less than 3,000,000 but more than 50,000 inhabitants each year may petition the Department to receive additional compensation based on performance. To receive additional compensation, the official's assessment jurisdiction must meet the following criteria:
For purposes of this Section, "coefficient of dispersion" means the average deviation of all assessments from the median level. For purposes of this Section, the number of inhabitants shall be determined by the latest federal decennial census. When the most recent census shows an increase in inhabitants to over 50,000 or a decrease to 50,000 or fewer, then the assessment year used to compute the coefficient of dispersion and the most recent year of the 3-year average level of assessments is the year that determines qualification for additional compensation. The Department will promulgate rules and regulations to determine whether an assessor meets these criteria.
Any assessor in a county of 50,000 or fewer inhabitants may petition the Department for consideration to receive additional compensation each year based on performance. In order to receive the additional compensation, the assessments in the official's assessment jurisdiction must meet the following criteria: (i) the median level of assessments must be no more than 35 1/3% and no less than 31 1/3% of fair cash value of property in his or her assessment jurisdiction; and (ii) the coefficient of dispersion must not be greater than 40% in 1994, 38% in 1995, 36% in 1996, 34% in 1997, 32% in 1998, and 30% in 1999 and every year thereafter.
Real estate transfer declarations used by the Department in annual sales-assessment ratio studies will be used to evaluate applications for additional compensation. The Department will audit other property to determine if the sales-assessment ratio study data is representative of the assessment jurisdiction. If the ratio study is found not representative, appraisals and other information may be utilized. If the ratio study is representative, upon certification by the Department, the assessor shall receive additional compensation of $3,000 for that year, to be paid out of funds appropriated to the Department from the Personal Property Tax Replacement Fund.
For State fiscal years beginning on or after July 1, 2023, the Department shall remit to the applicable township or county the amount required for the additional compensation under this Section. That money shall be deposited by the township supervisor or county treasurer into a fund dedicated for that purpose. The township or county payroll clerk shall pay the bonus stipend to the assessor within 10 business days after those funds are deposited into the township or county fund. The bonus stipend shall not be considered part of the assessor's base compensation and must be remitted to the assessor in addition to the assessor's annual salary or compensation. Beginning July 1, 2023, the township or county shall be responsible for the State and federal income tax reporting and withholding and employer contributions under the Illinois Pension Code, if applicable, on the additional compensation under this Section.
As used in this Section, "assessor" means any township or multi-township assessor, or supervisor of assessments.
35 ILCS 200/4-20