Rethinking Interviews: The Overlooked Science Behind Hiring

Interviews are often considered the gold standard for evaluating candidates during the hiring process. They give us insights into a candidate's qualifications, personality, and cultural fit. However, after concluding a recent interview process and reflecting on the feedback, I realised that my understanding of interviews needed rethinking.

Coincidentally, while taking a psychometric course, I discovered a surprising truth: interviews are a form of psychometric assessment. Like tests, interviews are designed to predict future performance by assessing a candidate's knowledge, skills, and abilities. However, unlike psychometric assessments, interviews often need more structure and rigour to deliver reliable and valid results.

To explore how others view interviews, I conducted a LinkedIn poll to assess how best described in the selection process, and the results were unsurprising (my sample size was very small, and this was the result at the time of posting this blog):

-Psychometric assessment: 0%
- Technical evaluation: 23%
- Behavioural assessment: 38%
- Cultural fit assessment: 38%

It became clear that many professionals do not associate interviews with psychometric tools, even though, when appropriately structured, they can provide invaluable predictive data. In this post, I will unpack why interviews must be viewed through this lens and how organisations can significantly enhance their hiring processes by applying psychometric principles.

The Science Behind Interviews

At their core, interviews and psychometric assessments share the same objective: gathering data to predict future job performance. For these predictions to be accurate, both need to be evaluated for reliability (consistency of results) and validity (how well they measure what they claim to). Unfortunately, most interviews—particularly unstructured ones—fall short of these standards.

Unsurprisingly, bias is one of the most significant sources of error in interviews. Research shows that interviewers often form an opinion about the candidate within the first few minutes and spend the rest of the interview confirming that initial judgment. This confirmation bias undermines the reliability and objectivity of interviews. Structured interviews, when used well, can provide a way to overcome this problem. Interviewers can move beyond snap judgments and assess candidates more fairly and accurately when they use predetermined, job-relevant questions.

 Key Findings

As I delved deeper into the research, several critical points emerged that illustrate why interviews need to be treated with more structure and objectivity:

1. Bias is the greatest source of error.
This could be either confirmation bias or candidates are judged based on one outstanding characteristic, a phenomenon known as general standoutishness. Bias can also be found in cross-ethnic, cross-cultural, and cross-class interviewing.

Interesting even though first impressions are seen as crucial in job interviews, with factors like professional attire, grooming, competence, and friendly nonverbal cues playing significant roles. However, research has shown that while individual tactics like wearing perfume or using positive nonverbal behaviours can enhance an applicant's ratings, combining multiple strategies can backfire as interviewers may perceive overly polished candidates as manipulative.

2.  Structured Interviews Improve Reliability 
It's no surprise that research shows that structured interviews—where the same set of questions are asked to all candidates—lead to more consistent and reliable results. Structured interviews ensure fairness and objectivity, instilling confidence in the accuracy of predictions about job performance.

3.  Cultural Fit and Behavioural Assessments Dominate 
While assessing a candidate's cultural fit and behavioural traits is important, it sometimes overshadows the need to evaluate job-specific skills and competencies. Over-focusing on cultural fit may exclude talented candidates who bring diversity in background or personality but have the right skills for the job.

4.   Active Listening Is Crucial
Effective interviewing requires a flow of conversation where interviewers ask open-ended questions and actively listen to the candidate's responses. This approach not only allows interviewers to gather deeper insights but also encourages them to be more engaged and attentive, providing more meaningful information.

5.   Interviews Are Psychometric in Nature 
At their core, interviews are designed to gather data about a candidate’s capabilities and potential. To unlock their full potential, interviews need to be treated like psychometric assessments, focusing on structure, fairness, objectivity, and predictability of job performance.
 
What This Means for Your Hiring Process
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If we view interviews as a form of psychometric assessment, it becomes clear that we must apply the same level of care and precision. Here are some ways to improve your interview process:

1.  Standardise Your Interviews 
There are no surprises here. Develop a set of predetermined, job-relevant questions that assess the candidate’s knowledge, skills, and abilities. This creates a level playing field and ensures that each candidate is evaluated on the same criteria.

2.  Reduce Bias with Structure 
Structured interviews reduce the risk of bias by minimising the influence of first impressions. Techniques like panel interviews, predetermined questions, and note-taking help interviewers focus on relevant data rather than subjective judgments.

3.  Focus on Predictive Data 
Ensure that your interview questions are designed to predict job performance. Ask questions that reveal how a candidate has applied their skills in the past or how they would handle specific challenges in the role you're hiring for.

Most interviewers use a nominal scale (poor, fair, good, very good, excellent) to assess candidates' responses. When using these scales, it is important to ensure a common understanding of what they mean, as they are prone to ambiguity, misclassification, observer bias, or inconsistency.

4.   Train Interviewers 
Psychometrics is usually carried out by trained personnel, and interviewers should also be trained. Interviewers must be trained and motivated to form an accurate impression of the interviewee. They must focus more attention on the interviewee to notice, remember, and use individuating information that is not consistent with initial perceptions. They must focus on information that is predictive of job performance.

The use of active listening and open-ended questions is a must to create a more engaging and informative interview. This helps interviewers gather valuable insights without being influenced by superficial factors. It is important to note that the participants in an interview influence each other. A good interviewer knows how to provide a relaxed and safe atmosphere through social facilitation.

5.   Good interviewing is actually more a matter of attitude than skill. 
Research has found that the employment interview often involves a search for negative or unfavourable rather than favourable evidence about a person. Attitudes related to good interviewing skills include warmth, genuineness, acceptance, understanding, openness, honesty, and fairness.
 
6.   Use Interview Data as Hypotheses 
Treat the data collected from interviews as a starting point, not the final word. Use interviews in combination with other assessments to make more informed hiring decisions.

 A Quote to Reflect On
The employment interview, at its core, is a psychological test. It is a systematic attempt to assess personality, ability, and other factors predictive of success in a particular role."
– John E. Hunter & Ronda L. Hunter

 A Question to Reflect On
Are your interviewers trained to maximise the collection of relevant, predictive information about candidates?

Conclusion
Interviewing is a scientific process that should be approached with the same rigour as psychometric testing. By reducing bias, increasing structure, and focusing on job-related data, we can transform interviews from subjective conversations into reliable predictors of job performance. It is worth reflecting on how interviews are conducted in your organisation occasionally and taking steps toward a more structured, fair, and effective process.

Further readings 
Psychological testing: Principles, applications, and issues" by R. M. Kaplan & D. P. Saccuzzo

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