Further analysis using a similar data set to the McDaniel, Whetzel, Schmidt and Maurer (1994) meta-analysis of employment interviews was performed in the present study, in order to investigate four possible causes for the apparent superiority of individual employment interviews. These causes included (a) criterion contamination of individual interview studies, (b) greater prevalence of psychologists performing individual interviews, (c) greater number of trained/experienced individual interviewers, and (d) greater prevalence of high proximity to target positions in individual interviews. A research question was also proposed to investigate whether all interview panel sizes were inferior to individual interviews in terms of validity. Meta-analyses using 204 job and training performance validity coefficients indicated that individual interviews were superior in validity to panel interviews, but only when the criterion was training performance. Training/experience was the only explanation for the superiority of individual interview validity, such that individual interviewers were more likely to be trained/experienced, suggesting that individual interview validity was superior as a result. The explanation that the use of psychologists in interviews may account for superior individual interview validity was only partially supported. While psychologists were more prevalent in individual interviews, individual interview validity was lower than that of panel interviews, when the criterion was job performance. Only when training was the criterion was individual interview validity higher when psychologists were interviewers. Two hypotheses were not supported. Firstly, there was no evidence of criterion contamination inflating individual interview validity. Secondly, no relationship between interviewer proximity and interview validity was found. Investigations of whether all panel sizes were inferior in terms of validity found that panel sizes of more than three members were superior in validity to individual interviews, when the criterion was job performance.