Ten elementary special education teachers in a rural educational cooperative implemented specific curriculum based measurement and data utilization procedures with at least two students each over one school year. Three data utilization strategies (no data utilization, therapeutic analysis, and experimental analysis) were compared in terms of their effects on the number of modifications teachers made in the students' programs, and student performance. Teacher preferences for therapeutic and experimental strategies, as well as for two measurement procedures (mastery and performance measurement) were examined also. Results indicated that teachers made more instructional changes and student performance increased more when specific data utilization strategies (therapeutic or experimental) were used. Further, teachers preferred therapeutic analysis over experimental analysis and performance measurement over mastery measurement. (Author)