Illinois Child Support Law: A Proposal to Change from the “Percentage Of Income” Formula to an “Income Share” Model

Currently, Illinois uses a “percentage of income” formula to calculate a parent’s child support obligation to the custodial parent. This formula calculates child support by multiplying the noncustodial parent’s net income by a certain percentage to determine that parent’s guideline child support obligation. The guideline percentage varies depending on the number of children between the parties. For one child, guideline support is 20% of the noncustodial parent’s net income. For two children, it’s 28%. For three, it’s 32%, and so on. This way of calculating a noncustodial parent’s child support obligation has been in effect since the 1980’s and some argue it is due for makeover.


For one, opponents of Illinois’ current calculation method argue that it fails to automatically take into account the income of the custodial parent. Rather, in Illinois, the court will determine strictly by looking at the noncustodial parent’s income in the overwhelming majority of cases. In order for a court to consider the custodial parent’s income, the noncustodial parent would have to specifically request that the court deviate from statutory guidelines. Deviation often requires negotiation and litigation. In the end, the court will determine how much to deviate from guidelines based upon what the judge believes to be fair. As a result, outcomes may vary from case to case and courtroom to courtroom.


Take, for example, the recently-decided case of the Marriage of Turk. In that case, the custodial father made over $150,000 per year, while the noncustodial mother earned less than $10,000 per year. As a result, the court actually ordered the custodial parent to pay child support to the noncustodial parent, so that she could provide for the children when they were visiting with her. While the Supreme Court eventually decided that the current child support law does permit such an outcome, the parties had to litigate the case all the way up to the Supreme Court over a period of several years to obtain that result. Worse, the Supreme Court then remanded the case for further evidentiary hearings to determine what each parent’s child support obligation should be. Most people simply can’t afford that sort of court battle, financially or emotionally.

Opponents of Illinois’ current child support law also argue that it ignores the amount of time the noncustodial parent spends with the child, which yields unfair results. For example, if a father has six overnights in a two week period with the mother having eight, he still may be obligated to pay the guideline percentage, even though he has possession of the children only one night less each week than the mother. Under current Illinois law, if the father wants a reduction in child support based upon his parenting time with the children, he would have to seek a deviation. Those who want to change Illinois’ child support law to an income shares model claim that it’s better for the child, since it may result in less conflict in such cases, and therefore, fewer custody battles. Given Illinois’ current guidelines and procedure for seeking a deviation, their argument seems fairly intuitive.


Finally, Illinois’ child support law does not explicitly provide for “split-custody” situations, in which one or more children live with one parent and another child or other children live with the other parent. As a matter of practice, lawyers will commonly take the position that each parent should pay the other the statutory guideline child support, but there is nothing in the current law which requires that outcome.


So what is the alternative to the current child support statute?


Over the past few years, various committees and organizations, including the Child Support Advisory Committee and the Illinois Department of Healthcare and Family Services, have recommended that Illinois change its current method of calculating child support to the “income share” method, which the majority of states currently use. In fact, thirty-eight states currently use what is known as the “income share” model. For a list of which states use either model, click here.


In states using the “income share” model of calculating child support, the state publishes a table that estimates the amount of money that an intact family would spend to meet the needs of their child or children. The parents’ combined incomes are listed in rows, and there are columns for the number of children. To determine the basic child support obligation, simply find the appropriate intersection on the grid. Colorado’s child support guideline table is a good example.


Once the basic child support obligation has been determined according to the table, income share model assigns a percentage of that obligation to each parent, based upon his or her share of the family’s total income. In other words, if each of the parties earns approximately the same amount of money, the noncustodial parent’s basic child support obligation would be 50% of the amount on the chart. If, on the other hand, the noncustodial parent earned more money than the custodial parent, his or her percentage share of the child support obligation would increase. Essentially income share model attempts to ensure the children receive the same financial support as they would have if the family remained together.


Once the basic child support obligation has been determined, most states allow for adjustments for things such as the amount of time each parent has the children, the amount of money each parent spends on support-related expenses such as healthcare, daycare, and the like. The state publishes a worksheet in which the parties can simply plug-in the appropriate amounts for such things and calculate the support obligation owed by the noncustodial parent. Colorado’s worksheet is a good example.


As an example, suppose Tom has an income of $7,000.00 each month and Katie, with whom their two children reside, has an income of $3,000.00 each month. Presume that Katie works and spends about $800.00 each month on childcare during the periods in which she is at work. Presume that one of the children has special needs and has a recurring monthly medical expense related to her care in the amount of $200.00 each month.


Combined, Tom and Katie have a monthly income of $10,000.00. Using, the Colorado’s income share formula, the base-line child support obligation would be $1,844.00. Adding the $800.00 for childcare and $200 for extraordinary medical expenses of $200.00, the total obligation is $2,844.00. Taking the proration of income, Tom would pay Katie 70% of the total obligation or $1,990.80.


The income share model also offers a mechanism for shared parenting time to be included in guidelines calculations, if the parenting time meets a certain specified minimum threshold.


Interestingly, in most cases, both methods produce similar results. However, the results using the income share model are more noticeable when one parent’s income is significantly higher than the other’s.


For more information regarding Illinois child support laws and procedures, please contact us.

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