Interrogation and interview: strategies for obtaining clinical data.

During assessment of 55 outpatients, we recorded the numbers and kind of health problems noted during an open-ended interview and during an ;interrogation' based on a structured questionnaire. The combined strategies (interviews and questionnaires) identified a total of 269 problems which were clinically important (i.e. needed medical attention). One hundred and ninety-eight of these problems (74 per cent) were identified by the open-ended interview. Thirtyeight (14 per cent) were identified only by the interview, 71 (26 per cent) only by the questionnaire. We observed that few of the problems detected only by questionnaire were acted upon and that they were therefore only marginally important; most of the problems noted only during interview did lead to further medical action and so were unequivocally of clinical importance. Our data suggest that an open-ended interview, undertaken with the intention of identifying all the patient's health problems, detects those problems well. The routine addition of a lengthy interrogation adds little and is therefore unnecessary.