The Chicago Tribune article on assessments has a comment on what constitute acceptable real estate assessment quality.
It states that a 15% margin of error is “the highest acceptable coefficient of dispersion (margin of error).”
Accuracy in your township
Experts say the highest acceptable coefficient of dispersion, or COD [margin or error], is 15.
See how your township compares with others in the same triennial reassessment area by entering a street address.
Information for Cook County is contained below that statement.
The average margin of error is 23.5%.
Here is the 2015 information for McHenry County:
So what does living in a township like McHenry or Richmond or Burton with margins of error of about 20% mean?
Over the years while wrestling with trying to explain Coefficients of Dispersion (“margins of error” in human terms), I came up with the following.
>Assuming that a sales tax rate is 10% (I used 5% in past days), a 20% COD would mean that if three shoppers spent $100, one would pay $12 in sales tax, a second $10 and a third $8.
There’s an equal chance for each result.
Think of the fights one would have at the checkout line.
Another way of explaining it is that with a COD of 20%:
- Half of the properties are assessed within the range of the median = or – 20%.
- The other half are assessed higher or lower.
That’s how bad real estate assessments are in McHenry, Burton and Richmond Townships.
They are worse in all but Grafton, Dorr and Nunda Townships.