We do not yet know for certain whether desegregation works because the goals of desegregation are so amorphous and the research conducted so far is inadequate to prove whether racial composition has an independent impact on student achievement. Desegregation is a complex issue whose nature is not known and may not be discovered because attempts to measure its effectiveness interfere with attempts to understand its complexities. One of the complications of desegregation is that many schools remain segregated even after desegregation plans have been implemented. In effect, these districts have become resegregated through the placement of students into tracked programs on the basis of their scores on achievement tests. The courts have held such practices to be unconstitutional. Tests cannot be used for placement purposes when the grouping that results reinforces the past effects of discrimination without providing the support to help minority students move from one group to another. Grouping or labeling without supportive instruction or appropriate diagnostic and instructional techniques thwarts desegregation. Answers to a series of questions such as whether tracks correspond to class and race, and whether parents can review placements, can be used to determine if student assignments are educationally justified. (Author/IRT)