Testing. Taking a test or filling out a questionnaire the first time may sensitize the client so that subsequent scores are influenced. This is particularly important with single-system designs...

Testing. Taking a test or filling out a questionnaire the first time may sensitize the client so that subsequent scores are influenced. This is particularly important with single-system designs because of reliance on repeated measures. Example: The staff of the agency filled out the evaluation questionnaire the first week, but most staff members couldn’t help remembering what they said that first time so that subsequent evaluations were biased by the first set of responses.