Social media sites such as Facebook, TikTok, and Instagram have given many organizations a new hiring tool. According to a 2018 CareerBuilder survey, 70% of employers check out applicants’ profiles as part of their screening process, and 54% have rejected applicants because of what they found. Social media sites offer a free, easily accessed portrait of what a candidate is really like, yielding a clearer idea of whether that person will succeed on the job—or so the theory goes.

However, new research suggests that hiring officials who take this approach should use caution: Much of what they dig up is information they are ethically discouraged or legally prohibited from taking into account when evaluating candidates—and little of it is predictive of performance.

Read more about Chad Van Iddekinge's research in Harvard Business Review.