Interviews are by far one of the most commonly used personnel selection tools because they work, at least when they are structured interviews.
One potential problem with interviews is that irrelevant personal characteristics of interviewees (e.g., gender, race) may affect interview ratings. Interviewees who are similar (race, gender) to interviewers may receive higher ratings in an interview than those who are dissimilar to the interviewers. This can ultimately lead to illegal practices and failing to hire the best applicants. This potential problem is known as demographic similarity. The underlying reason this may occur is that people view others who are similar to themselves more favorably than those who are different.
ARE THERE DEMOGRAPHIC SIMILARITY EFFECTS?
Researchers (McCarthy, Van Iddekinge, & Campion, 2010) focused on highly structured job interviews, which are known to be more valid and effective than unstructured interviews. The researchers found that the demographic similarity effect was completely non-existent in highly structured interviews. In fact, their results suggest that there is no such thing as a demographic similarity effect when highly structured interviews are used.
Impressively, the study was conducted on a total of 207 interviewers and nearly 20,000 entry level employees applying for professional level positions with the U.S. government. Moreover, the findings were consistent across three common types of structured interviews: (1) past-behavioral based interviews, (2) interviews focusing on a person’s past experiences and education, and (3) situation-based interview (e.g., asking what applicants would do in a specific hypothetical situation.)
Not only are highly structured interviews legally defensible and able to effectively target high future performers and weed out poor performers, we now know that they are highly resistant to demographic similarity effects. The authors offer a few quick tips for ratcheting up the structure of a job interview: (1) keep the questions of all applicants consistent and avoid shooting from the hip, (2) base interview questions off of a formal job analysis, (3) include ratings that have anchors with behavioral examples, (4) have interviewers take thorough notes during an interview, (5) avoid discussing applicants between interviews, and (6) include a panel of interviewers or raters as opposed to a single interviewer.
McCarthy, J. M., Van Iddekinge, C. H., & Campion, M. A. (2010). Are highly structured
job interviews resistant to demographic similarity effects? Personnel Psychology, 63(2), 325-359.