Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
ALTERNATIVE MODEL DESIGNS: PROGRAM PARTICIPATION FUNCTIONS AND THE ALLOCATION OF ANNUAL TO 89 MONTHLY VALUES IN TRIM2, MATH, AND HITSM 3 Alternative Model Designs: Program Participation Functions and the Allocation of Annual to Monthly Values in TRIM2, MATH, and HITSM Constance F.Citro and Christine M.Ross INTRODUCTION The Transfer Income Model 2 (TRIM2) and the Micro Analysis of Transfers to Households (MATH) model are two microsimulation models that are heavily used for analysis of proposed changes to government tax and transfer programs. The Household Income and Tax Simulation Model (HITSM) is another static microsimulation model that has been used for policy analysis in the income support and tax areas. All three models fall into the class of âstaticâ microsimulation modelsâthat is, models that operate on a cross-sectional basis and make projections to future years using procedures for reweighting, or âaging,â their database to match outside projections of selected characteristics such as the demographic and labor force composition of the population.1 (In contrast, dynamic models apply transition probabilities for events such as birth, death, job change, and others to the records in their database, thereby âgrowingâ their population year by year into the future; see Ross in this volume.) Constance F.Citro is a staff officer at the National Research Council; she served as study director of the Panel to Evaluate Microsimulation Models for Social Welfare Programs. Christine M.Ross is on the staff of Mathematica Policy Research, Inc.; she served as research associate of the panel. 1At present, users of TRIM2 do not normally invoke the model's static aging routines but instead apply out-of-model adjustments to project TRIM2 results obtained from the most recently available database.