What are the 15 most common types of interview biases?

Traditional hiring approaches tend to rely heavily on interviews as a selection method. This is despite decades of substantial evidence that interviews are not a good predictor of on-the-job-performance.

While interviews are generally ineffective, the fact is that almost all organisations still use them when hiring as the main, if not the only, selection tool. So if organisations are going to persist in interviews, it’s important to be aware of the issues that can undermine accurately evaluating candidates’ interview performance. Being aware of your biases helps to reduce your hiring errors, and the huge cost of a bad hire.

Humans are, unfortunately, open to numerous cognitive biases. The work on cognitive biases was pioneered and popularised by the Nobel Prize winner Daniel Kahneman in his best-seller Thinking, Fast and Slow, first published in 2011.

Knowledge & awareness of cognitive biases is an essential skill to have these days. Did you know, you can assess your candidates’ knowledge of cognitive biases on Alooba?

When it comes to interviews, there are many types of bias that can easily creep into the process. It's handy to be aware of them and try to minimise them where possible. This helps to reduce your hiring error rate, as you can focus more on facts rather than feelings.

With the average cost of a bad hire at 15-21% of the employee’s salary, actively removing these biases from your interview process is worth the effort.

Here are 15 common types of bias that affect your interviews that everyone in the hiring process needs to be aware of.

1. Similarity attraction bias

You will naturally have an affinity for people who are somehow similar to you. For example they’re from the same town, support the same football team or have the same hobby. Therein lies the fundamental issue with the concept of a cultural fit interview, as they're inherently designed to hire people who will 'fit' in.

2. Illusory correlation

You think there's a connection between two things, when there isn't. For example, you might observe a candidate lacking confidence, and falsely think this means that they lack competence. This is not necessarily the case, and if anything, the opposite is true - there is a negative correlation between competence and confidence. This is famously called the Dunning-Kruger effect and is a common problem in hiring.

3. Confirmation bias

This is where you make your mind up early based on one thing, and then this clouds your judgement about everything else you hear after that. For example, you see the candidate worked in an outdated tech stack, so you assume they won't be able to adopt your tech stack, even if they then go on to prove that they easily could.

4. Availability heuristic

This bias is where you rely on immediate examples or easily accessible information to make judgments or decisions, neglecting relevant data that may be less accessible. For example, you interview a candidate and base your hiring decision purely on that, instead of measuring other things that like intelligence, skills & personality.

5. Anchoring bias

Anchoring bias occurs when you rely on the first piece of information you got, even if that information is arbitrary or irrelevant. For example, you start an interview and the candidate gives a sloppy handshake. The rest of your evaluation of them has now been tainted by that initial negative (and irrelevant) experience.

6. Hindsight bias

Hindsight is always 20-20, as they say. Hindsight bias happens when you think that events that have happened were more easily predictable than they were. For example when interviewing a candidate and they fail the interview, we might say ‘oh I knew they were going to fail - they didn’t look like they had the right experience’. The thing is, you wouldn’t have chosen to interview them if you didn’t think they had relevant experience, so you’re fooling yourself that you could have predicted this.

7. Overconfidence Bias

Overconfidence bias happens when you overestimate your own abilities, knowledge, or performance. For example, you might think that you can ‘just get a feel for someone’ by having a casual chat and that’s it. Or you might think ‘I don’t really need to have technical knowledge to interview them - if they can’t explain it to me simply then they mustn’t understand it.’ You have given yourself almost magical powers of intuition, that you simply don’t have.

8. Intuition Bias

‘Trusting your gut’ is basically relying on intuition to guide your decision making, and is probably the single most common bias that people have. If you interview a candidate who objectively scores well, but you still ‘feel off’ about them and you ‘can’t quite put your finger on it’, this is your intuition sending you down the wrong path. In hiring it’s crucial to put our feelings aside and just focus on things that are measurable.

9. Cognitive Dissonance

Cognitive dissonance refers to the discomfort when you hold conflicting beliefs or values. For example, you might interview a candidate and think ‘oh they came from a top tech company they must be good’ and ‘hmm, but they seemed quite uninterested in the interview, so they must not be good’. This puts your mind in a spin as you can’t reconcile the two conflicting narratives about the candidate.

10. Recency bias

Recency bias, as you’d probably guess, is the tendency to weigh recent information more heavily than older information. This comes into play in two different ways when interviewing. First, for a multi-stage hiring process, most companies seem to use a “one-strike-and-you're-out-policy”, whereby if the candidate bombs the last interview, it doesn’t matter how amazing they were in the first 3 rounds. Second, it’s common to favour the most recent candidate you’ve interviewed. This is especially problematic when you have a full day of interviews. Hiring managers often confide in us that, honestly, they can’t remember who they interviewed 1st during the morning by the time they’re done with their 6th interview of the day.

11. Stereotyping bias

We should all know about this bias, where just because someone belongs to a group, we make assumptions about them. For example when interviewing, we might think ‘Oh wow they’re coming from Google, they must be clever’ or ‘They’re from India, they probably won’t get our office banter.’

12. Information bias

This bias relates to always wanting to seek more information and more data points to make a decision, even when they’re irrelevant. This is quite common in hiring with things like reference checking, which typically becomes a tick-and-flick exercise and doesn’t really add any value. In interviews specifically, it’s really common for interviewers to ask totally irrelevant or stupid questions that don’t provide any insight. The hobbies section of a CV is also a good example - why does the candidate’s interest in water polo impact their ability to be a marketing manager?

13. Conservatism bias

This bias means that you favour existing or established understanding of things over new evidence. For example when hiring, it’s common for companies to still persist with CV screening despite the bias, and with unstructured interviews despite decades of evidence that they don’t work. Old habits die hard!

14. Bandwagon effect

This is basically the ‘group-think’ phenomenon of just adopting the same view as the general consensus around you. When interviewing, this frequently happens in the debrief session afterwards, where there’s a general discussion about the candidate where people will naturally agree with each other, or the HiPPO in the room.

15. Blind-spot bias

The final bias to discuss is definitely the most ironic, as we nearly left it out. Blind-spot bias is the inability for you to understand and acknowledge your own biases. So if you’ve looked at the list above and thought ‘Oh sure I’ve seen those in my colleagues’ and you don’t reflect on yourself, then you’ve got blind-spot bias. We hope this list helps you reflect on your own biases next time you’re hiring.

It should also be emphasised that being aware of our biases typically does not have much of an impact, which is why it’s genuinely crucial to implement unbiased, fair selection methods, such as skills-based hiring.