Individual interviews refer to interviews conducted by a single interviewer whereas panel interviews involve more than one interviewer. In the past, some researchers have suggested that panel interviews are superior to individual interviews because they allow more than one person to provide ratings (Warmke & Weston, 1992).
However, this argument doesn’t stand up to either practical or empirical scrutiny. In the first place, many organizations use multiple, individual interviews, which allow multiple raters to provide ratings.
Secondly, empirical research indicates that individual interviews are more valid than panel interviews (McDaniel, 1994). That meta-analysis, which was able to evaluate 144 validity coefficients across 23,308 people, in both panel and individual interviews, found that individual interviews were more valid than panel interviews for all types of interviews (i.e. both structured and unstructured) (.43 vs. .32), for structured interviews (.46 vs. .38) as well as for unstructured interviews (.34 vs. 33). The superiority of individual interviews seems to be greatest for structured interviews, whereas panel and individual interviews perform approximately the same for unstructured interviews.
While panel interviews are not really any more accurate, and may in fact be less accurate, there are some possible advantages to conducting multiple, individual interviews. Panel interviews may, in some cases, be easier for an organization to schedule. There is also the perceived value of having everyone in the same room, hearing the same things from the candidate. It may also improve the ability for interviewers to share their perceptions, ratings, etc. immediately after the interview is completed and therefore make faster decisions.
An organization may therefore prefer panel interviews from a stakeholder buy-in standpoint. From a pure accuracy standpoint, though, you would be better off conducting multiple, one-on-one interviews and then integrating the ratings.