Employers like to use free-form, unstructured interviews in an attempt to “get to know” a job candidate. Such interviews are also increasingly popular with admissions officers at universities looking to move away from test scores and other standardized measures of student quality. But as in my friend’s case, interviewers typically form strong but unwarranted impressions about interviewees, often revealing more about themselves than the candidates.

People who study personnel psychology have long understood this. In 1979, for example, the Texas Legislature required the University of Texas Medical School at Houston to increase its incoming class size by 50 students late in the season. The additional 50 students that the school admitted had reached the interview phase of the application process but initially, following their interviews, were rejected. A team of researchers later found that these students did just as well as their other classmates in terms of attrition, academic performance, clinical performance (which involves rapport with patients and supervisors) and honors earned. The judgment of the interviewers, in other words, added nothing of relevance to the admissions process.

Research that my colleagues and I have conducted shows that the problem with interviews is worse than irrelevance: They can be harmful, undercutting the impact of other, more valuable information about interviewees.