On July 1, 2017, a major change for calculating child support obligations takes effect. Last year, Public Act 99-764 was enacted. The legislation amended the Illinois Marriage and Dissolution of Marriage Act to replace the percentage guideline formula with the income shares model for calculating child support. This is a significant change that brings Illinois in line with 39 other states and the District of Columbia, which already use the income shares model.
Since 1984, Illinois has used the percentage guideline formula to determine child support. It arrives at the child support obligation by multiplying the payor's net income by a statutorily set percentage, which increases based on the number of children. This model is now considered outdated "because it does not reflect actual child rearing costs or allocate those costs between the parents." (Find out more more in the December 2016 IBJ at http://bit.ly/2qYq8Rr). Rather, the old formula required payors to simply pay a percentage of their net income regardless of the actual child rearing costs. Oak Brook attorney Margaret A. Bennett believes the old model often caused acrimony between divorcing parents because it is not always perceived as equitable and accurate.