Testing IDENTIFIERS Elementary Secondary Education Act Title I; *Normal Curve Equivalent Scores; *RMC Models

Normal curve equivalent achievement gains estimates were compared with RMC Title I evaluation Models Al and Bl. The 'comparison focused upon the amount of ties introduced by Model Al when its underlying assumptions were violated. The model assumes,.first, that the local school population is accurately represented by the national norm group; and secondly, that the percentile standing of the treatment group on the pretest remained unchanged on the posttest in the abscence of treatment effect. Data were from a Model 81 evaluation--kindergarten children were pre- and pcsttested with,the Aural Comprehension subtest of the Stanford Early School Achievement Test, while the first and second grade children were pre-_and posttested with the Woodcock Reading Mastery Test. Comparison of the three model B1 gain estimates (unadjusted, covariance adjusted, and principal-axis adjusted), illustrated the wide variation between estimates. For kindergarten groups, the adjustments were relatively modest, but for grades one and two, the adjustments caused a dramati