Does stress impact technical interview performance?

Software engineering candidates commonly participate in whiteboard technical interviews as part of a hiring assessment. During these sessions, candidates write code while thinking aloud as they work towards a solution, under the watchful eye of an interviewer. While technical interviews should allow for an unbiased and inclusive assessment of problem-solving ability, surprisingly, technical interviews may be instead a procedure for identifying candidates who best handle and migrate stress solely caused by being examined by an interviewer (performance anxiety). To understand if coding interviews—as administered today—can induce stress that significantly hinders performance, we conducted a randomized controlled trial with 48 Computer Science students, comparing them in private and public whiteboard settings. We found that performance is reduced by more than half, by simply being watched by an interviewer. We also observed that stress and cognitive load were significantly higher in a traditional technical interview when compared with our private interview. Consequently, interviewers may be filtering out qualified candidates by confounding assessment of problem-solving ability with unnecessary stress. We propose interview modifications to make problem-solving assessment more equitable and inclusive, such as through private focus sessions and retrospective think-aloud, allowing companies to hire from a larger and diverse pool of talent.