Effective August 1, 2005, the Child Support Guidelines changed dramatically. The former guidelines were based on economic data from 1999 and the guidelines themselves have a review process that includes consideration of more recent economic data. The commission for Child Support Guidelines contracted with a Denver company to develop a new schedule based on more recent economic data, to incorporate changes in the low income area, and to extend the schedule to include higher incomes. The guidelines allow for a calculation of current support based on each parent's share of the amount estimated to be spent on the child if the parents and child live in an intact household. Intact households are used for the estimates because of the guidelines' aim to provide children the same support they would receive if the parents lived together.

The United States Bureau of Labor Statistics produced a consumer expenditure survey. The survey data includes information on several hundred items purchased by households. The bureau categorizes these items into major categories such as food, housing, clothing, transportation, and health care. Excluded from these categories are personal insurance, savings accounts, pension plans, and mortgage principal payments. The mortgage principal payments are excluded as they constitute a form of savings.

The most important changes to the Child Support Guidelines are as follows: