The single best predictor of whether a person will demonstrate a competency in a job in the future is whether that person has demonstrated that competency in the past. The structured or focused interview is designed to gather evidence about past performance, which provides a predictor of future on-the-job performance.
The candidate is asked to recall specific experiences or events relevant to the job in question. Candidates are asked to provide detailed accounts, in response to carefully selected "trigger" questions. These questions are designed to encourage applicants to talk about situations that will generate appropriate data about past competence.
The Keil Centre's occupational psychologists have considerable experience in using this selection technique, and training / coaching others in its use. Structured interviewing is well proven as a fundamental part of a rigorous assessment centre.