What are the biggest mistakes hiring managers make in interviews—and how do they affect who gets the job?

The single biggest mistake is treating an interview like an informal chat rather than a structured assessment. When managers “go with their gut,” they open the door to unconscious biases that have a profound effect on who gets hired. This lack of structure allows biases like the halo effect (where one positive trait overshadows everything else) and affinity bias (our tendency to favor people like us) to take over.

As a result, managers often hire the person they like the most, not the person who is most qualified.

The solution is a structured interview. This involves two simple but powerful steps: First, Define the criteria first: Identify the essential knowledge, skills, and abilities (KSAs) for the role before looking at a single resume. Next, Use a consistent rubric: Ask all candidates the same job-related questions and score their answers using a pre-defined rating scale. This process transforms hiring from a subjective guessing game into an evidence-based decision, leading to fairer outcomes and a more talented workforce.