National Academies Press: OpenBook
« Previous: Operating Characteristics
Suggested Citation:"TRIM2 Parameters." National Research Council. 1991. Improving Information for Social Policy Decisions -- The Uses of Microsimulation Modeling: Volume II, Technical Papers. Washington, DC: The National Academies Press. doi: 10.17226/1853.
Page 174

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.

FUTURE COMPUTING ENVIRONMENTS FOR MICROSIMULATION MODELING 174 income taxes (FEDTAX), state income taxes (STATAX), supplemental security income (SSI), Aid to Families with Dependent Children (AFDC), food stamps (FSTAMP), child nutrition programs (CHINUT), state and local sales taxes (SALETX), state and local property taxes (HOUSE/PROPTX), Medicare and Medicaid (MEDIC), value-added taxes (VAT), and health insurance (HEALTH). The following master routines are used to read or to prepare the TRIM2 database for the simulation process by creating variables required by the major simulation modules: read input files (RDFILE), allocate annual income variables to monthly variables (MONTHS), create random-number variables (RANDOM), create filing unit variables (U8AFDC), adjust asset income (AINC), and impute federal tax deductions (FDIMPU). The following master routines are described below under Output Facilities: export data to an external file format (XPORT), tabulate differences in FSTAMP or AFDC simulations (SIMTAB), produce reports based on income distribution (QUANT), and create one or more output TRIM2 microdata files (WRFTLE). The following TRIM master routines are used to demographically and economically age a prospective TRIM2 microdata file (see Database Adjustment above): projecting the population or population aging (POPAGE), calibrating to a projected unemployment rate (CSWORK), and projecting total income or economic aging (ECONAGE). Most of these simulation and master routines are documented in the TRIM2 Simulation Modules (Webb et al., 1982) and the TRIM2 Reference Manual (Webb et al., 1986). TRIM2 Parameters TRIM2 uses two major types of parameters. Control or supervisor parameters are used to control the overall execution of a TRIM2 job. For example, the NPROC control parameter allows a user to specify the number of households to be processed. Simulation parameters are used to control the execution and output of a simulation module. For example, the FEDTAX simulation module accepts a DIVDEXCL parameter that permits a user to specify the amount of a dividend income exclusion. All TRIM2 parameters are defined and documented in the Central TRIM2 Directory (CTD). The CTD also contains the definitions of all TRIM2 variables and a history of all TRIM2 runs. The CTD is implemented using an indexed sequential access method. Originally, TRIM2 processed the CTD via COBOL subroutines that used the IBM Index Sequential Access Method (ISAM). These routines have now been converted to FORTRAN routines that use the IBM Virtual System Access Method (VSAM). When a data parameter is first entered into the CTD, its basic definition is given. This includes the parameter name; the parameter type (e.g., switch, integer, real); the maximum number of values; and a default simulation name. It is also possible to define an input data parameter that takes one or more parameter names as its values, so the CTD parameter definition also permits

Next: Model Execution »
Improving Information for Social Policy Decisions -- The Uses of Microsimulation Modeling: Volume II, Technical Papers Get This Book
Buy Paperback | $100.00
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

This volume, second in the series, provides essential background material for policy analysts, researchers, statisticians, and others interested in the application of microsimulation techniques to develop estimates of the costs and population impacts of proposed changes in government policies ranging from welfare to retirement income to health care to taxes.

The material spans data inputs to models, design and computer implementation of models, validation of model outputs, and model documentation.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook,'s online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  6. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  7. ×

    View our suggested citation for this chapter.

    « Back Next »
  8. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!