Comparison groups in research on families with mentally retarded members: a methodological and conceptual review.

A review and critique of the use of comparison groups in mental retardation family research was provided. Issues addressed include matching on age versus competency of the mentally retarded family member, description of comparison groups in published research, demographic equivalence of groups, matching strategies, populations from which samples were drawn, appropriateness of tasks/instruments across groups, and the role of theory in comparison group selection. Unique concerns relating to sibling research and studies of mentally retarded parents were discussed. Caution was expressed concerning the translation of comparison research findings into intervention targets for families with mentally retarded members. Alternatives to comparison group designs were presented as well as recommendations for selecting and describing comparison samples.