The equipercentile assumption states that students in traditional classrooms who receive no other instructional assistance, will maintain their relative rank order over time. To test this assumption, fall to fall test results on the SRA Achievement Tests were obtained for grades 2-3, and 6-7. Total reading and total mathematics growth scale values were used in all analyses. Score distributions were divided into low, medium, and high subgroups of an approximately equal number of matched scores. With the exception of grades 7-8 mathematics scores, the equipercentile assumption was valid only for certain subgroups, not for the total group. These results conflicted with those of a similar study the previous year, providing less than a harmonious picture of the equipercentile assumption. Districts considering Title I evaluation model A should conduct a local study of non-federally impacted children to determine for themselves the appropriateness of the assumption. (CP)