The National Center for Education Evaluation and Regional Assistance produced this major study of the effectiveness of education technology. Mandated by Congress, the report uses scientifically based research methods and control groups to focus on the impact of technology on student academic achievement. Thirty-three districts, 132 schools, and 439 teachers participated in the study. Sixteen products were selected for the study based on public submissions and ratings by a study team and expert review panels. This report is the first of two from the study. The second report will present effects for individual products. The current report presents effects for groups of products. The main findings of the study are: (1) Test scores were not significantly higher in classrooms using the reading and mathematics software products than those in control classrooms. In each of the four groups of products-reading in first grade and in fourth grade, mathematics in sixth grade, and high school algebra-the evaluation found no significant differences in student achievement between the classrooms that used the technology products and classrooms that did not; and (2) There was substantial variation between schools regarding the effects on student achievement. Although the study collected data on many school and classroom characteristics, only two characteristics were related to the variation in reading achievement. For first grade, effects were larger in schools that had smaller student-teacher ratios (a measure of class size). For fourth grade, effects were larger when treatment teachers reported higher levels of use of the study product. The following are appended: (1) Data Collection Approach and Response Rates; and (2) Estimating Effects and Assessing Robustness. (Contains 36 tables, 12 figures, and 1 exhibit.) [This report was published by the Institute of Education Sciences' National Center for Education Evaluation and Regional Assistance.]