This report focuses on the severe reduction in sample size caused by the introduction of experimental controls in research with schizophrenic Ss and the limitations which this places on the generalizing of findings to the total population of schizophrenics. The selection procedures of a representative study were examined, and it was found that Ss meeting the selection criteria represented only 11.4% of the male schizophrenics in the hospital and 25.6% of all those meeting age and chronicity requirements. More detailed reporting of the degree of sample shrinkage and increased restraint in the generalizing of findings were recommended for studies using schizophrenic Ss.
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