Witness Interview Training: a Field Evaluation

The effect of a witness interviewing training program on interviewing performance in actual investigations was examined. Eighty interviews, conducted by police officers in one Canadian organization, were coded for the presence of 38 desirable practices. Results showed that, in general, trained interviewers outperformed their untrained counterparts. Specifically, there was a large improvement in engage and explain behaviors (d = 1.65), a moderate improvement in account behaviors (d = 0.54), and a large improvement in closure behaviors (d = 0.90). Trained interviewers also used more open-ended questions and fewer leading questions. The implications of the findings for transferring interviewing skills from the classroom to the field are discussed.