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DOCUMENTATION FOR MICROSIMULATION MODELS: A REVIEW OF TRIM2, MATH, AND HITSM 338 which is a tabulation subprogram that produces output reports, are documented in Simulation Modules. Furthermore, the utility programs that TRIM2 uses are documented in a chapter of the Reference Manual, but QUANT and RANDOM, which seem to be utilities, are included in Simulation Modules. The Reference Manual has chapters on databases, conversion of public-use survey microdata files into TRIM2 format, and file aging. However, AINC, a subprogram of the aging modules, is documented in Simulation Modules. Furthermore, MONTHS, FDIMPU, and HOUSE, which seem to be pure imputation routines, also are included in Simulation Modules.3 To their credit, the Urban Institute staff have automated the documentation process in the Central TRIM2 Directory apparatus. This routinization of the process should greatly enhance the availability of and priority placed on documentation. The Simulation Modules document was produced totally by the automated process. The documentation for each module has a short statement of purpose, summaries of subroutines, standard parameters, data parameters, and specifications for input and output variables. A nice feature of the software that produces the documentation is that it produces a table of contents with page numbers. On the other hand, the individual tables of contents that precede the chapters in the Reference Manual lack page numbers, which severely limits their usefulness. A disadvantage of the software is that it limits the graphics that can be used. In particular, flowcharts, example input, and sample printout would enhance many of the descriptions. The Simulation Modules documentation is voluminous; the AFDC module description itself is 283 pages. Nevertheless, the software creates helpful header information on each page. One disappointment is that references to external source documents are somewhat hard to locate (a separate section is recommended) and are usually incomplete. In some instances, references are missing altogether. For example, the AFDC participation algorithm uses a probit function, but the documentation does not cite any source documents. Suggestions The following suggestions are based on this limited review of the documents: 1. The documentation for TRIM2 should be carefully reviewed by a content editor to eliminate inconsistencies such as obsolete cross-references. Also, the editor should point out places where sources need to be identified (completely). Presumably, consistency checking can be implemented in the automated documentation software, so that when portions of the documentation are updated, all relevant references can be updated. 3It is not clear why FDIMPU is documented separately from FEDTAX or why HOUSE is documented separately from PROPTX.