Common Rater Biases


Before beginning your evaluations, you should familiarize yourself with some common rater biases. A bias is a preconceived notion or prejudice you have based on your perspective or experience. It’s important to acknowledge your biases so they have less impact on the interview process - the first step to overcoming biases is to recognize and become aware of them.  


Many people have preconceived notions about a candidate before they ever meet them – perhaps from something on their resume, their name, the school they attended, or an assortment of other reasons. These first impressions can have a lasting impact on our decisions. However, it’s important not to rely on irrelevant information about the candidate when evaluating their interview performance. Instead, carefully attend to all of the candidate’s responses to better understand their past experiences and behaviors. By keeping an open mind, you’ll be able to uncover more information about the candidate - and it may or may not align with your initial impressions. 

Halo and Horn Effect

This refers to the tendency to see people as all good or all bad, rather than seeing them as a blend of strengths and weaknesses. The best way to counter the Halo and Horn Effect is to evaluate candidates against each key competency for the job. Think about each competency individually and objectively, then evaluate the candidate on that competency independent of other areas. 

“Similar to Me” Error

We all tend to like people who remind us of ourselves, or who have characteristics that we admire in ourselves. The bias to favor those who are similar to us is quite powerful and extremely common; however, it is important to keep in mind that candidates who are very different from you may still be a good fit for the role. 


We have a natural tendency to lump people into categories. Sometimes we generalize characteristics to groups, or assume that because a person has Characteristic A, they must also have Characteristic B. This can result in positive or negative stereotyping. Rather than making assumptions about a candidate’s strengths or weaknesses based on other information about them, you should independently evaluate each of the candidate’s interview responses against their target job competencies. 

First/Last Effect

This is the tendency to be overly influenced by information that a candidate presented very early or very late in the interview. To combat this effect, listen carefully and take notes throughout the interview – that way you can refer to all relevant information when making your evaluations, rather than just the candidate’s opening or closing statements. 

Contrast Effect

When conducting multiple interviews, we may allow our perceptions of previous candidates to influence our ratings of the present candidate. This is particularly pronounced when previous candidates performed very well or very poorly. Instead of thinking about previous candidates when making evaluations, be sure to rate the present candidate according to the objective standards provided for each interview question. 

Leniency/Severity/Central Tendency

This refers to raters who are too lenient, too harsh, or hesitant to rate outside of the average when evaluating others. An interviewer rating one candidate low or high is not indicative of a bias - but if the trend persists across candidates, the rater may have their own expectations for interviewees that are not tied to the objective standards used in the interview.  

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