We have always relied on interviews to hire people. What does a behavioural assessment actually add, and is it worth the extra step?
It is a question more organisations are asking, and the answer comes down to understanding what each tool is actually measuring, and where each one tends to let you down.
Let's start with the traditional interview.
The interview has been the cornerstone of hiring for generations, and it has real strengths. It allows you to meet a person, observe how they communicate, assess whether they can articulate their experience clearly, and get a sense of how they might fit within your team and culture. For many roles, that human connection matters, and a skilled interviewer can draw out genuinely useful information through well-constructed questions.
The problem is that most interviews are not as reliable as we believe them to be.
Research consistently shows that unstructured interviews, the kind where the conversation flows naturally and questions vary from candidate to candidate, have surprisingly low predictive validity when it comes to actual job performance. Interviewers tend to make a judgement within the first few minutes and spend the rest of the conversation confirming it. This is known as Confirmation Bias, and its very real. Candidates who are articulate, confident, and personable tend to perform well in interviews regardless of their actual capability in the role. And candidates who are less comfortable in a formal interview setting, but potentially exceptional performers, can be screened out for the wrong reasons entirely.
Structured interviews with consistent, competency-based questions improve that picture meaningfully. But even the best structured interview is still measuring how someone performs in an interview. Not how they will perform in the role.
That is the gap that behavioural assessment addresses.
A well-designed behavioural assessment is not measuring how someone presents on a given day. It is measuring how they are naturally wired to think, decide, communicate, and respond under pressure. It identifies the tendencies that show up consistently across time and context, the patterns that a single conversation, however well-conducted, simply cannot reliably reveal.
The evidence base here is clear. Structured psychometric and behavioural assessments have significantly higher predictive validity for job performance than interviews alone. They are less susceptible to first impression bias, less affected by a candidate having a good or bad day, and less dependent on the skill of the individual conducting the assessment.
It is also worth noting what behavioural assessment adds beyond the hire itself. Understanding how a new team member is wired to work allows their leader to onboard them more effectively, communicate with them in a way that actually lands, and identify early where they are likely to thrive and where they may need additional support. The insight does not stop being useful once the offer is accepted.
The most effective hiring processes do not choose between interviews and behavioural assessment. They use both, at the right stages, for the right purposes. The interview tells you how someone presents and whether they can articulate relevant experience. The behavioural assessment tells you how they will actually show up in the role, in the team, and under the pressures that come with it.
Used together, they give hiring leaders a genuinely more complete picture, and a much stronger foundation for a decision that carries significant consequences either way.
If you are curious about how behavioural assessment could strengthen your existing hiring process, our team is happy to walk you through what that looks like in practice. Reach out to us at hello@peakoutput.com or visit www.peakoutput.com to start the conversation.
