Research clearly shows that structured interviews are one of the most valid methods for selecting employees and that unstructured interviews are not good predictors of future performance. Clarifiers are questions that clarify information on the applicant's resume or application blank. Another example would be an applicant with a two-year gap between jobs. A logical clarifier is to ask what the applicant was doing during those two years. The answers to clarifiers are not used to predict future performance, thus they are not scored.
Qualifiers are questions that determine if the applicant has the minimal qualifications for the job.
Past-focused questions , also called behavioral questions, are designed to tap an applicant's experience. Tell me about the best Web page you ever designed. Imagine that you stopped a motorist for speeding and she claimed to be going into labor. You don't see any signs of her going into labor. A customer claims that his steak was not cooked properly.