Ability is difficult to define, and students placed in homogeneous groups based on ability in one area may not be of similar abilities in other areas. While research has not clearly shown homogeneous grouping to be beneficial, its potential for harm is revealed in several studies. Such grouping can cause students to lose motivation for a variety of reasons at all ability levels; stratification of students by socioeconomic class is encouraged; the positive effects high achievers can have on low achievers are eliminated; and students with discipline problems tend to be grouped together. The concept of ability grouping in America is financially, legally, and philosophically questionable as well. Alternatives to across-the-board ability grouping include grouping for ability in specific subject areas, encouraging such individualized programs as peer-tutoring, and the enrollment of advanced high school students in college classes. The distinction between these techniques and the ability grouping methods that have developed since the late 1950s is that these alternatives are varied, voluntary, and supplementary to the proven traditional system of heterogeneous grouping. (Author/PGD)