How to reduce subjectivity in the interview with prior evidence

You can’t eliminate bias from an interview: a person makes the decision, and people have biases. What you can do is reduce the room subjectivity has to influence it. Three things help: using a common criterion for all candidates, anchoring questions in prior evidence and not just in impression, and taking notes during the conversation. That helps you control subjectivity, not eliminate it.

It’s best to start with the uncomfortable truth: no interview is fully objective, and be wary of anyone who promises otherwise. The interview is a conversation between people, and there’s always impression, chemistry, likability there. The realistic goal isn’t to erase all of that, it’s to keep it from deciding for you without you noticing. And for that, there’s method.

Where subjectivity slips in

The unstructured interview concentrates the weight of the decision on impression, and impression is exactly where biases enter most. Some of the most common:

• Halo effect. A striking quality (they speak very well, they come from a well-known company) colors the rest of the assessment.
• Similarity. We tend to favor those who resemble us: same background, same references, same style.
• Order. The first or last candidate carries different weight just because of their place in line.
• Confirmation. Once you’ve formed a first impression, you look for signals that confirm it and ignore those that contradict it.

None of these disappear through willpower. But their influence can be contained.

What actually helps control it

There’s no magic solution; there are practices that move the needle.

1. A common criterion for everyone. Same base questions, same way of reading the answers. If each candidate experiences a different interview, you’re comparing impressions, not people. We develop this in structured vs. unstructured interview.
2. Prior evidence, not just impression. Come to the conversation with comparable signals on each candidate, so you don’t rely solely on the chemistry of the moment.
3. Notes during, not judgment after. Write down what the person said while they say it. If you wait until the end, your memory has already rearranged everything in favor of the first impression.

The role of prior assessment

Assessing before interviewing doesn’t make the decision automatic or take it out of human hands. What it does is give you a comparable baseline: all candidates went through the same yardstick before personal impression comes into play. So when you get to the interview, your questions anchor in something concrete and not just in how the person came across in the first two minutes.

This reduces the weight of factors like similarity or order, because you already have evidence to look at beyond the conversation. But it’s important to be clear: prior evidence supports the decision, it doesn’t make it, and the team can still have biases when interpreting it. The tool helps control subjectivity; it doesn’t eliminate it. See how that baseline is used in comparing candidates with a common criterion.

What not to promise (to yourself or your internal client)

It’s tempting to say “with this there’s no more bias.” Don’t say it, because it isn’t true and it shows. The honest and defensible version is: “we structure the interview and support it with prior evidence to reduce the weight of impression, though the final decision is human and can have biases.” That sentence survives any internal audit; the other one doesn’t.

In short

Don’t eliminate bias —you can’t— reduce its room. Use a common criterion for all candidates, anchor questions in prior evidence, and take notes during the conversation. Prior assessment gives you a comparable baseline that helps control subjectivity, but the decision remains human and can have biases. To put it into practice, check out how to prepare the interview with evidence or the product.