405 ILCS 5/5-116
The Department shall establish a standard by which shall be measured the ability of responsible relatives to provide support, and shall implement the standard by rules governing its application. The standard and the rules shall take into account the buying and consumption patterns of self-supporting persons of modest income, present or future contingencies having direct bearing on maintenance of the relative's self-support status and fulfillment of his obligations to his immediate family, and any unusual or exceptional circumstances including estrangement or other personal or social factors, that have a bearing on family relationships and the relative's ability to meet his support obligations. The standard shall be recomputed periodically to reflect changes in the cost of living and other pertinent factors.
405 ILCS 5/5-116