Back in the 1970’s, Algonquin Township Assessor Forrest Hare computerized his office, probably the first to do so in the State of Illinois.
He also took an interest in how assessment could be made more accurate.
Hare looked at measures of accuracy called “Coefficients of Dispersion.”
I figured out that calling them “margins of error,” terms used in polling, would make the measures more understandable.
A good COD or margin of error was and I suspect is 10%.
That’s not particularly good, but assessing real estate is not an exact process.
If one had a sales tax of 5%, which Illinois did in the 1970’s, a margin of error of 10% would mean that half the people buying $100 worth of goods would pay between $4.50 and $5.50 sales tax.
The other half would pay more or less than that range.
So,for purposes of equity, it is important to keep the margin of error as low as possible.
What Hare found was that there was a break point of about 5,000 people between better assessments and those which were really bad.
My guess was that with more than 5,000 people, a township could afford to have a full-time assessor, which would result in more accurate assessments.
Based on that research, I introduced a bill to create Multi-Township Assessors.
On a voluntary basis, the bill, which is now state law, a township board could agree with one or more other township boards to create the elective office of Multi-Township Assessor.
Townships under 5,000 people in McHenry County as of the 2010 Census follow:
- Alden – 1.402
- Coral – 3,522
- Dunham – 2,844
- Hartland – 2,031
- Hebron – 2,356
- Seneca – 2,944
- Riley – 2,922
Burton was just three people over 5,000.
The other problem with having assessments done by a jurisdiction with a small number of properties is that there is a small number of sales.
Below are the Coefficients of Dispersion (among other information published by the Illinois Department of Revenue for those townships in McHenry County with enough sales to calculate statistics:
Let me pull off the township margin of error numbers to make them easier to read:
- Algonquin – 38.23%
- Burton – 37.04%
- Chemung – 46.16%
- Dorr – 27.07%
- Grafton – 46.26%
- Greenwood – 27.71%
- Marengo – 38.71%
- McHenry – 29.24
- Nunda – 37.69%
- Richmond – 40%
Data for all the other smaller townships are aggregated. That means the averages represent no particular township. Some townships may be assessed way higher or lower than others.
All other – 30.68%
The average Coefficient of Dispersion for McHenry County was 35.45%.