Intervirew Bias

How to Reduce Interview Bias

One of the most important decisions you will make as a hiring manager is who to hire. The cost of a bad hire adds up and can be as much as 3.5 times the annual salary for the position that you are trying to hire for. One of the most common tools used in the hiring process is the interview. Unfortunately, many interview processes are full of interview biases that can lead to bad hires, an unfair hiring process, and a lack of diversity in your organization. With over 180+ cognitive biases out there, it can be a real challenge to figure out where to start and how to reduce the impact of interview bias when hiring.

What are cognitive biases?

Cognitive biases are errors related to how we think and process information. Our brains are always looking for shortcuts to simplify how we see the world and take in information. These shortcuts happen so that we can make decisions more quickly and efficiently. We all have biases, no matter how objective we believe ourselves to be. The impact of cognitive biases on our day-to-day lives is typically unimportant, but in certain situations, such as the interview, it becomes critical to try to reduce these biases.

Types of interview bias

Here are 4 common interview biases, and examples of how they might show up.

First Impression Bias
First Impression Bias is a cognitive bias in which you are influenced by the first piece of information you receive, whether positive or negative. This bias can impact the interview if you are impressed (or unimpressed) by your first impression of the candidate. This first impression influences your hiring decision. For example, candidates are more likely to be hired if they:

  • Give a firm handshake
  • Make good eye contact
  • Are well dressed
  • Strike up good conversation before the interview

Obviously, none of these factors are directly related to whether the person will be successful on the job. What can you do to combat first impression bias and make sure you are making objective decisions?

  • Make sure your interview scoring criteria are directly linked to successful job performance. Use this scoring criteria (and only this scoring criteria) to assess candidates (e.g., there should be no place to score the firmness of handshakes).
  • Make sure your rating scale is as objective as possible (e.g., Behaviourally Anchored Rating Scale). Subjective rating scales are more prone to interview bias.
  • Take detailed notes and encourage other interviewers to do the same. This allows you to justify your interview scores. Additionally, this practice also helps with legal defensibility in case a hiring decision is ever challenged.
  • Have a scripted opening to the interview and scripted interview questions to ensure all candidates receive the same information.


Similar-to-me Bias
Similar-to-me bias is a cognitive bias in which we tend to favour other people who are the same as us. The similarity can span a variety of dimensions including race, gender, age, values, and beliefs. In a hiring context, you tend to give higher ratings to candidates who are more like you. This practice is problematic because departments end up with a bunch of replicas of the hiring team, which has negative implications on diversity and performance. What can you do to combat similar-to-me bias when hiring?

  • Don’t use the “beer test” (i.e., would the team enjoy having an after-work beer with this candidate?) as an indicator of “fit” within the team or organization.
  • Don’t ask irrelevant questions that could feed into similar-to-me bias (e.g., What do you do for fun? What’s the best thing you’ve watched recently?)
  • Clearly identify the knowledge, skills, and abilities required for the role before starting the selection process and stick to questions related to these.
  • Use a structured interview process to ensure consistency and fairness across all candidates.


Halo and Horn Bias
The halo and horn effect are cognitive biases in which one positive/negative impression of people can impact your perception of them in other areas. For example, people who are well-liked might be perceived as more intelligent and competent than they actually are. These biases can impact the interview by allowing your impression of a candidate on one question to cloud your perception of them on other questions. For example, the horn effect may influence you to score a candidate lower on an interview question because they “bombed” the previous question. What can you do to combat the halo and horn effect when hiring?

  • Make sure interview questions are scored completely independent from one another.
  • Make sure all scoring criteria are as objective as possible. Subjective criteria are more prone to interview bias.
  • Make sure to score each question in real-time, rather than waiting until the end of the interview to score all questions. If you wait until the very end of the interview, your overall impressions of the candidate, as well as other biases, are more likely to influence your ratings of each individual question.


Confirmation Bias
Confirmation bias is one in which we collect evidence that confirms our pre-existing expectations or beliefs. We tend to seek out information that confirms our views while ignoring information that may disprove these views. In a hiring context, confirmation bias can lead you to spend more time focusing on information that confirms your view of a candidate. For example, you might be very impressed by a candidate’s resume, and spend the entire interview looking for information that confirms this initial view. Or you may strongly dislike a candidate’s previous employer, and spend the entire interview looking for reasons not to hire the candidate.
What can you do to combat confirmation bias when hiring?

  • Clearly identify the knowledge, skills, and abilities required for the role before starting the selection process; stick to questions related to these.
  • Have a scripted opening to the interview and scripted interview questions to ensure all candidates receive the same information.
  • Use a panel interview. Individual biases are more likely to be “canceled out” when you use a panel. But beware of conformity bias – adjusting your opinions so that they align with the opinions of others.


5 Steps to Reduce Interview Bias

Although we can not train ourselves out of bias or completely eliminate them, we can implement practices that help us to reduce bias. Here are 5 steps you can take to reduce bias during the interview.

1. Link Questions to Job Requirements
You should identify the knowledge, skills, abilities, and other characteristics (KSAOs) required for the role before starting your selection process. These KSAOs should be identified by talking to and working with people who are familiar with the role. During the interview, stick to questions related to critical KSAOs. For example, if teamwork and problem solving are critical for the role, you should be asking interview questions that assess teamwork and problem-solving.

2. Use an Objective Rating Scale
Subjective rating scales are more prone to bias. Subjective rating scales use criteria that are not well defined, and too open to interpretation. Here are two examples of poor quality, subjective rating scales:

Bad rating scale

This type of rating scale tends to result in little differentiation between candidates, with a lot of candidates scoring near the middle (meets expectations) of the scale. The vague criteria make it challenging to score accurately. For example, what’s the difference between an outstanding applicant and a very good applicant? You and other hiring managers might have a different idea of what each of these looks like.

Instead, use objective criteria that are linked to the requirements of the job. The most objective and accurate rating scale you can use is a Behaviourally Anchored Rating Scale (BARS). BARS define specific behaviours across the different levels of proficiency that you can assess candidates against. For example, here is a BARS for an interview question that measures problem-solving:

Interview Rating Scale

3. Score Questions in Real-Time
Don’t move onto the next interview question until you have scored the current question. Scoring questions in real-time increases accuracy, decreases bias, and ensures that the candidate provided you with enough information to score the question. Relying on your memory at the end of the interview (or worse, the end of the day!) is a sure-fire way to let bias seep into your process. You should also take detailed notes for each question in real-time so that you can look back at your notes to justify the score that you gave.

4. Use a Structured Interview
A structured interview is the most reliable and accurate kind of interview. A structured interview should include a scripted opening and scripted questions to ensure all candidates receive the same information. It is also critical that you use an objective rating scale to make sure all candidates are scored fairly and consistently. Here is an example of a structured interview question and rating scale for assessing continuous learning skills.

competency based interview

Competency based rating scale

5. Use a Panel
We all have different individual biases. By using a panel interview our individual biases are more likely to “cancel out.” When using a panel, make sure all interviewers are properly trained, so that you are all on the same page in terms of what the interview is assessing and how to use the scoring criteria. Leave time at the end of the interview for the panel to discuss any differences in scores and arrive at a consensus for the overall rating.

In summary, cognitive biases such as first impression bias, similar-to-me bias, halo and horn bias, and confirmation bias can negatively impact our perceptions of job applicants. Fortunately, there are structures we can put in place to reduce these biases and make more fair and objective hiring decisions. To learn more about how we can help to reduce bias and add objectivity to your hiring process, go check out our hiring check-up.


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