The behavioral interview seeks the actual behavior in a context, while the situational interview elicits 'espoused behavior' which is what the candidate thinks he will do. It is believed actual behavior is a better predictor of future behavior rather than espoused behavior. However, very little research has been done on espoused behavior; lots of research has been done on actual behavior as a predictor. It is claimed, based on meta-analysis of pooled data, that the rating in the interview has a correlation of 0.64 with the first rating on the job in case the interview is a behavioral event interview (BEI).
The BEI needs to be analyzed using what is called CAVE (Content Analysis of Verbal Expression) or LACS (Leeds Analysis). Very few corporate HR managers possess the required skills, so they resort to conducting a conventional interview and label it as a BEI. Be wary of such corporate honchos.