The apparent simplicity of this question is il- lusory, and the difficulty of arriving at a simple answer is in great measure The panel would like to thank Gaea Leinhardt, who helped gather evidence and who con- sulted extensively with us during the preparation of this chapter.
74 Effective Instruction 75 a function of the difficulty of deciding who is and who is not mildly men- tally retarded.
Our question then becomes: What is effective education for mildly men- tally retarded students?
In addition to problems created by shifting definitions of the EMR population?
there are reasons for the lack of evidence that lie deep in the prevailing tradition of educational research, a tradition in which re- search on mental retardation has quite naturally shared.
As mentioned pre- viously, the jury is still out as to the most effective placement for these students.
As we noted in Chapter 2, the variation and changes in the definition of educable mental retardation complicate the task of deciding what is effec 76 REPORT OF THE PANEL five education for mildly mentally retarded children, since it is unclear who should be classified as mentally retarded.
Chapter 3 presented our view that the justification for assessment procedures derives from their contribution to effective teaching and learning.