Being aware of bias is the first step for eliminating it from your interview process.

Of course, you hire the best person for the job. That’s what you strive to do. Your company prides itself on its diversity program, and you truly mean that. You make sure that every candidate is given equal consideration and that you select the best person each time.

Are you sure? You may be biased in ways that you don’t expect–ways that have nothing to do with the obvious ways people make hiring mistakes. Your biases can appear in other ways, and while you still get good people when you interview with bias, you may not get the best candidates.

emphasisHR talked with me about the surprising way your biases influence you’re hiring. Here are four ways your bias might be preventing you from making the best hire:

Cultural Stereotypes

“If the interviewer has a preconceived notion of how an interviewee’s ethnicity will affect their job performance, this could greatly impact the hiring decision,” warns emphasisHR. This isn’t always negative towards the candidate–it’s just as easy to give someone extra points because of their ethnicity as it is to have a negative viewpoint.

Contrast Effect.

Did you know that if you interview someone who is just not a good fit at all, that can make the next candidate look even better than she is? The next candidate is so much better than the last one that she seems to shine, even if she’s not the best candidate for the job.

Negative Emphasis Bias

emphasisHR points out that “tend to weigh negative information more heavily than positive information.” They give an example that occurs commonly in job interviews:

Let’s say in the beginning of the interview, the candidate reveals, if hired, he will not be able to start in the position for three weeks. You were hoping to find a candidate who would be able to start immediately, so this is bad news in your opinion. For the rest of the interview, it’s possible that this could overshadow everything positive that the applicant has to say because you are still stuck on that tidbit of negative information.

While you tell yourself you’d be willing to wait an extra week for the best candidate, everything this candidate says is colored by this, and it makes it difficult to judge him fairly.

Choice-Supportive Bias

Did you have to fight to get a candidate on the interview list? Did you argue that a person from your Alma Mater should be interviewed even though others didn’t think she was one of the best candidates? While what you tell yourself is that you want these people to have a chance, what happens is that you perceive their interviews in a much more positive light because you made the choice to bring them in. You’re not so much fighting for the best candidate as you are fighting to validate your own choices.

How Do You Stop Biased Interviewing in Your Workplace?

Of course, you can’t do it altogether–we’re all human, but emphasisHR gives some tips.

• Make sure all interviews are in the same place to “level the playing field.”
• Have a structure to your interviews. List the skills you are looking for and have each interviewer assign a numerical rating for each candidate.
• Take great notes. You may be prone to a “contrast bias” effect after interviewing a terrible candidate, but after looking at your notes you can determine that the following candidate wasn’t truly the best candidate–she just seemed that way because she was so much better than the person before.

This article was originally published at Inc.com.