Illinois courts have stated that when a lack of uniformity in the
assessment process is the basis of an appeal, the disparity of
assessments must be proved by clear and convincing evidence. The
Property Tax Appeal Board has ruled that isolated examples of
assessment inequities are not sufficient to substantiate an assessment
reduction. When the
assessment of a residential property is at issue, the Board usually
rules that the assessment comparables must be located in the same
neighborhood or subdivision as the subject. Proof of assessment
inequity should consist of more than a simple showing of assessed
values per square foot of the subject and the alleged comparables.
There should also be a showing of physical, locational, and
jurisdictional similarities as well as market value considerations.