The RMC Research Corporation evaluation model C1--the special regression model (SRM)--was evaluated through a series of computer simulations and compared with an alternative model, the norm referenced model (NRM). Using local data and national norm data to determine reasonable values for sample size and pretest posttest correlation parameters, the simulations used normal curve equivalent (NCE) scores with 200 repetitions for 10 sample sizes, three levels of correlation, and three ability levels. The results indicate that: (1) the standard errors of the estimates of project effectiveness are quite large in many cases and have a strong dependence upon the size of the comparison group; (2) as implemented through NCE scores, the procedure has a small bias; and (3) when project effectiveness estimates are obtained using the inappropriate norm referenced model, the bias may be large enough to suggest that the results are educationally significant even in cases where there is no real effect. (Author/CTM)