Interviewer bias & common interviewer mistakes

What is interviewer bias?

Interviewers are only human and human beings are prone to a range of biases and errors that can affect the effectiveness of interviews.

Under normal circumstances these biases are in fact shortcuts that the brain uses to quickly make sense of the barrage of information we are presented with when dealing with other people.

When interviewing candidates it’s essential that we are conscious of these automatic (and biased) ways of dealing with information in order to prevent errors affecting outcomes.

Interviewer bias and interviewer mistakes

Interviewer mistakes: Common errors and biases made by interviewers

Some errors can occur during the interview while others tend to affect the assessments and ratings we make after the interview.

Errors that can affect assessor/interviewer performance include:

Halo & Horns effects

The Halo & Horns effects occur when interviewers give similar ratings to separate aspects of a candidate’s performance even when those dimensions are clearly distinct. It is like putting a halo over (or horns on) the candidate’s head and saying they are all good (or all bad) rather than having a range of strengths and weaknesses. Possible reasons for the Halo or Horns effects are:

  • Failure to attend to all assessment criteria, therefore focusing on a few
  • Confirmatory biases – focusing on similarity rather than difference
  • Discounting of inconsistent information
  • Lack of knowledge (or acceptance) of the distinct differences between the assessment criteria
  • Comparing the candidate to someone they know well and assuming they are alike in all respects

Primacy and recency

Primacy (or first impressions) is said to have occurred when the interviewer gives more weight to the first impressions they formed of the candidate. Having made a quick decision about the candidate’s suitability early in the interview the interviewer subsequently does not pay attention for the rest of the meeting.

Recency also results from a lack of concentration. In this case the interviewer only remembers events from the end of the interview. In the cases of both primacy and recency the middle of an interview is the time when interviewers are most likely to lose concentration.

At the end of the interview the interviewer rates the performance of the candidate. This evaluation process is subject to a number of errors. These common errors are reflections of the idiosyncratic use of the rating system by the interviewer rather than the true reflection of the performance of the candidate.

It is important that interviewers use the scales in a consistent way otherwise comparisons between candidates interviewed by different interviewers become meaningless.


Leniency is the tendency to give high ratings and no low ratings. Interviewers are lenient for many different reasons. Some of the more common ones are:

  • A desire to be liked and not to be critical
  • Unwillingness to justify low ratings and negative comments
  • Concern that other interviewers are also lenient
  • Low standards
  • Poor questioning or listening


Severity is the tendency to only give low ratings. Severity sometimes occurs when interviewers:

  • Have a desire to be seen as tough
  • Do not understand that in this process high scores need to be given
  • Possess attitudes about high ratings that are carried over from appraisals or peer reviews

Central tendency

Central tendency happens when the interviewer only gives middle ratings (typically 3 or 4 out of 5, or the amber). The reasons for central tendency include:

  • Unconscious tendency to overuse the middle rating
  • Unwillingness to stick one’s neck out
  • Inadequate observation
  • Unwillingness to justify high or low ratings


Be sure to compare the candidate’s performance with the selection criteria on the assessment form and not in comparison with the other candidates you have seen. A mediocre candidate could be wrongly evaluated as good or even excellent if they are preceded and followed by poor ones.

First impressions

Placing excessive importance upon what is observed during the first few minutes at the expense of subsequent behaviour. Some candidates may take time to get warmed up in an interview.

Exaggeration of negatives

Taking good behaviour for granted, but exaggerating the importance of certain negative behaviours and evaluating these more harshly than the positive ones.


Results from interviewers letting impressions from other sources over-influence evaluations (e.g. having expectations of a candidate because you know how they performed on a separate assessment or test).

Avoiding errors in assessment

The bottom line when you are assessing and interviewing is that you are making decisions that will have a profound effect on a whole range of people’s lives:

  • The candidate you hire
  • The candidates you reject
  • Members of the team that will have to work with the new recruit
  • Their boss
  • Their customers

It is therefore a serious responsibility for interviewers to be aware of the common errors in assessment and to constantly monitor their own performance for any sign of errors. This responsibility reflects obligations placed on the interviewer by employment law, business needs and ethical assessment standards.

Interviewer bias and interviewer mistakes

Common interviewer biases

A structured approach to selection using structured interviews helps businesses to be more objective in choosing their employees. Human beings, however, do not process information objectively. We add our own beliefs, values, and biases when we judge the behaviours of others.

Minimising the impact of our own biases starts with being aware of them.

Deep down we all have our own biases. Some individuals have characteristics that we have problems with. These can be based on stereotypes, or may have been part of our own upbringing. Whatever the cause, the result can be that some candidates are less favourably treated because of the interviewer’s bias. The following list provides some examples of possible biases that can impact on objectivity in assessment:

Similar to me

Interviewers who view a candidate more favourably because he or she reminds them of themselves, are subject to the similar to me bias. This can be in relation to their background, experiences, and so on.

Regional accents

Many people find particular regional accents off-putting. They may also associate stereotypical characteristics of a region to an individual with that accent.


An applicant who dresses in a particular way, whilst not unsuitable but which is not to your personal taste, may be viewed less favourably. Or someone with a hairstyle you do not like, or with bitten fingernails, may lead you to attribute characteristics to them that are not backed up by their actual behaviour.

Ethnic origin

It is unlawful to treat an individual less fairly because of their ethnic origin.


It is unlawful to treat an individual less fairly because of their gender.


By discriminating against someone because of their age, you could be losing someone with all the right qualities and a wealth of experience. And it’s illegal.

Interviewer bias and interviewer mistakes

Minimising interviewer bias

To minimise the impact of assessment errors and personal biases on the assessments of candidates you should take account of the following points:

  • Be aware of your own personal biases
  • Begin observing the interview with a completely open mind
  • Pay attention to the candidate
  • Listen objectively to what the candidate says
  • Suspend your judgement during the interview
  • Use notes as a useful memory jogger to help maintain objectivity when you are evaluating the evidence and making a decision

Employment law obligations in the UK

Because of the impact of this, a number of checks and balances are enshrined in law to protect all concerned parties.The employment equality legislation prohibits two types of discrimination:

  • Direct discrimination – when an employer treats an individual less favourably for employment opportunities because of their sex, race, age or any disability, orientation etc.
  • Indirect discrimination. The resultant discrimination may be intentional or otherwise. For example, excluding applicants on the basis of childcare responsibilities is a form of indirect discrimination and is illegal.

Other legislation applies similar approaches to discrimination on the grounds of race, ethnicity and disability.

Staying within the law

To keep your interview questions legal make sure you can answer these two questions positively:

  • Is the question/assessment comment related to the job? You should be able to demonstrate that the questions relate directly to critical criteria identified for the role.
  • Is the question/assessment comment relevant to any candidate? If the questions would be irrelevant or unfair to any candidate do not ask the question.

Interviewer bias and interviewer mistakes

Want to improve your interviewing skills? Check out some of our other blog posts; how to be a good interviewer, what is impression management? Good interviewer skills, Strategic interview questions to ask candidates.


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