This study used a mixed-methods approach to explore the perceptions of a heterogeneous sample of 75 police interviewers regarding their performance in a mock interview with a 5-7 year old child. Each officer recruited for this study was authorised to conduct investigative interviews with children. Specifically, we explored how the officers'perception of what makes a good interview differs depending on their background experience and their (perceived and actual) ability to adhere to best-practice interview guidelines. Overall, the officers' perceptions of what constitutes an effective interview were not entirely consistent with those held by experts in forensic interviewing. The majority of the interviewers perceived that the locus of control in the interview rested primarily with the child and/or the environmental setting. In contrast, experts tend to place the central onus of responsibility for the outcome of an interview on the skill of the interviewer in using open-ended questions. Several possible explanations for, and the implications of, these findings are discussed.