Staff of the House Budget Committee supplied the CDA with sufficient detail on the House Budget Resolution to allow Center analysts to simulate the fiscal effects of changes in tax law and major programs and outlay categories. Details on the steps taken to incorporate these policy changes in the model are contained in Appendix 2 to this report. What does policy simulation mean? Model simulation of public policy change requires two sets of data. First, estimates of how the changes affect outlays and revenues, which become the policy inputs to the dynamic model. Second, analysts.