A year long study involving 38 students in grades 1 to 6 was conducted to assess the degree of implementation of a frequent, curriculum-based measurement and evaluation system in classrooms in which the teachers had received training in the system, and to examine the effectiveness of the measurement and evaluation system in terms of enhancing the structure of the instructional lessons and students' reading achievement. The results indicated that although teachers were skillful in the measurement part of the system, they were unsuccessful in applying the evaluation components; students' instructional programs seldom were changed. In terms of the structure of the lessons, only one of the 12 structure variables (controlled practice) yielded significantly higher ratings for experimental than for control subjects. The remaining 11 variables favored experimental subjects, but were not statistically significant. No statistically significant differences in achievement were found between the two groups. All students improved over time. The results suggested that the implementation of a frequent curriculum-based measurement system is feasible and successful in improving the structure of instruction. Achievement effects may be manifest if the evaluation components are applied. (Author)