This study was made to (1) compare Michigan middle schools with junior high schools on the basis of selected ongoing programs and practices, and (2) determine if the two organizations differed in any way. Proportional stratified sampling provided a selection of 138 junior high schools that could be compared with the 138 middle schools in the State. A survey instrument mailed to principals of the participating schools provided the data for the study. Investigators found that (1) most of the organizational structures and instructional processes of both school types are similar to predecessor programs and instructional organizations for the middle years; (2) middle schools were primarily established to reduce overcrowded conditions in other schools, whereas the junior high school organization was to provide a program specifically designed for students in the age group served. (Author/MLF)