The junior high school, typically grades 7-8 or 7-9, offers a program that is "not-quite-yet-but-trying-to-be" a high school. The organization of the middle school (commonly the grades 6-8), however, is based on a philosophy of education that was specifically designed to meet the special needs of a preadolescent learner; middle schools incorporate unique curricula to better effect the transition between elementary and high school programs, rather than attempt to approximate one or the other. Many educators, perceiving junior highs as a "failed" promise, have turned to the middle school philosophy as an affirmation of a higher level of commitment. Indeed, since 1964, the number of new middle schools replacing traditional junior highs has progressively increased. A review of research on middle-level education indicates that: (1) although primarily an administrative concern driven by attendance boundaries, grade level organization had little impact on middle-level students' academic achievement; and (2) the terms "junior high school" and "middle school" do not define a school's program. Additionally, the effective schools research has given rise to discriminant analyses of effective middle school variables and allowed researchers to identify those characteristics most commonly found within "exemplary" middle schools. (159 references) (KM)