The gap-reduction model has been identified as a potential alternative to or extension of the Title I Evaluation and Reporting System (TIERS). The gap-reduction model has been recommended for the evaluation of bilingual programs, but has only recently been given consideration for evaluating local Chapter 1 programs. This report recommends that projects use local comparison groups and examine multiple outcomes, but voices concern that state educational agencies (SEAs) and local educational agencies (LEAs) will lose sight of the benefits of the gap-reduction model because of significant technical problems with interpreting Relative Growth Indices (RGIs) as an extension of routine Model A analysis. The report discusses the following three issues: (1) the validity of the RGI; (2) conditions for aggregation; and (3) data quality. The following recommendations are presented: (1) do not require aggregating RGIs, but rather encourage piloting the gap-reduction model as a means to augment local evaluations; and (2) encourage LEAs to use annual testing and explicitly allow selection on the pretest at the local level, then leave the gains "uncorrected," acknowledging that they are measures of relative gain, or adjust the results downward to better estimate treatment effects. The report includes one figure and four sample tables. (AF)