It's no secret that first impressions are powerful, particularly in the setting of a job interview. But just how much time does it actually take a hiring manager to measure up an employee and make a decision?

According to a recent study published in the Journal of Occupational and Organizational Psychology, the answer is not much – but perhaps more than you were expecting.

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The study involved setting up interviews between 166 interviewers and nearly 700 undergrad and master's students at a U.S. university. All of the student participants were in the process of applying for real jobs. The interviews were each 30 minutes long.

According to the findings, the majority of interviewers (60 percent) said they had made their decision within the first 15 minutes of the interview. Of that group, nearly 26 percent made theirs in the first five minutes. Only 5 percent actually made their decision in the first minute.

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The rest of the interviewers (40 percent) said they were able to come to a decision after 15 minutes or after the interview was over. So, for the job seekers out there, if you're concerned that you're somehow doomed from the moment you sit down, it seems that statistically, that isn't the case.

The researchers also found that the structure of the interview could also factor into the decision making process. If you have a list of questions that you pose to every applicant, that kind of set up can lead to a slower conclusion. Meanwhile, a more conversational, informal style of interview that is more about developing a rapport can lead to faster decisions.

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The professors hold that veteran interviewers are more likely to make faster decisions about a candidate than their less practiced counterparts. However, those less experienced interviewers could also be influenced in their decision by the rapport they've built with the applicant.

They also noticed that interviewers take longer to decide about applicants earlier in the process than at the end. Their recommendation for businesses looking to hire was to keep the number of consecutive interviews to four to prevent that kind of snap judgment burnout.

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