You need to hire a new employee for a key role. You could make the hiring decision on your own, but experience has taught you that hiring is an imperfect science. You've hired people you were convinced would be exceptional who turned out to be duds. You've also hired people who turned out to possess talent you never imagined. 

So you add two colleagues to the hiring process. Being able to compare notes, to compare impressions, to discuss the strengths and weaknesses of each person--since a hiring decision is often a judgment call, three people's judgment is bound to be better than one. 

Depending on what happens when you actually meet to make the hiring decision.

According to research detailed in Noise: A Flaw in Human Judgment, the new book by Daniel Kahneman (author of Thinking, Fast and Slow), Olivier Sibony, and Cass Sunstein, the quality of the group decision will depend on when, and how, each of your individual insights is shared.

Yep: Like many things in life, it's all about the timing.

The First Opinion Shared Can Make a Huge Impact

Let's start with who goes first.

In a 2013 study published in Science, researchers attempted to determine the impact of initial feedback. Using a website that allowed readers to comment on stories, they arbitrarily gave up-votes or down-votes to any comment when their vote could be first. (In short, if you posted a comment and the researchers could leave the first up- or down-vote, they did.)

If you're the second voter, whether the first vote was positive or negative shouldn't sway you. And that was, in fact, largely true when the first vote was negative. 

But when the initial vote was positive, that increased the likelihood the next vote would also be positive by 32 percent. Even months later, after studying the results of more than 100,000 posts, researchers determined that after an initial positive vote the mean rating of votes tended to be 25 percent higher.

Yep: If the first opinion was positive, subsequent opinions were much more likely to be positive -- even though that first opinion was the result of a virtual coin flip. 

The result is what the researchers termed "accumulated positive herding." 

In terms of making a hiring decision, the first opinion shared -- especially when it's positive -- can significantly influence the opinions of everyone else on the hiring team. 

As can the subsequent discussion.

Sharing Opinions Can Make Those Opinions More Extreme

In a 1998 study published in Journal of Risk and Uncertainty, researchers conducted a series of experiments using mock juries whose task was to determine punitive damages for a theoretical product liability case.

They found that the process of deliberation, a process that should benefit from combining the judgment of six people, negatively impacted the result. 

Even though the facts of the case were the same, different juries delivered very different settlement amounts. Why? One person tended to have an outsize impact on the final decision.

If the median member of the jury -- the person who wasn't the least inclined to award damages, and not the most, but somewhere fell in the middle -- favored awarding relatively low damages, the group's verdict tended to skew toward a substantially lower award than initial individual opinions would have indicated.

But if the median opinion fell well to the side of the "let's make the [jerk] pay" spectrum, the group tended to skew toward a much higher award than initial individual opinions would have indicated. In fact, one in four of those mock juries chose to award damages that were as high -- and even sometimes higher -- than the highest member's initial opinion. 

That result is what social scientists call "group polarization."

Which means, once the members of the hiring team share their opinions with one another, they are more likely to feel even more strongly that a certain candidate should be hired. Or that a certain candidate should not.

And it gets even worse.

Sharing Opinions Can Create the Wrong Kind of Consensus

Pretend you're one of the three people who meet to make the hiring decision. A colleague, Phyllis, speaks first. She feels strongly that one candidate -- we'll call her Angela -- is the best choice. She quickly lists a few reasons and sums up. "I think she's perfect," Phyllis says.

Now it's your turn. You were impressed with Angela. But you felt Kelly had a number of strong suits as well. (Yes, I saw an episode of The Office last night.) 

Phyllis's judgment makes a big impact on you, though. While she listed only a few reasons why Angela is the right choice, still, Phyllis is smart. She's savvy. She's hired more people than you.

So you go with Angela.

Now it's Creed's turn to share his opinion. Coming into the meeting he had major reservations about Angela. But he's the junior member of the hiring team. Expressing a different opinion puts him in a vulnerable position; you and Angela might think less highly of his judgment -- and of him -- in the future.

So he goes with Angela. You all go with Angela.

Deciding to hire Angela is what social scientists call an "informational cascade." Granted, she might have been the best candidate. 

But maybe she wasn't. Maybe, if Creed had gone first, his negative opinion would not have sparked accumulated positive herding. Maybe the polarization sparked by Phyllis's "I think she's perfect" comment would have been lessened. (Maybe, after hearing what Creed had to say about Angela's answers to his behavioral interview questions, she wouldn't have made that comment at all.)

Maybe everyone in your group would have been willing to dig deeper to find objective, more substantive differences in the candidates.

And maybe you would have made a different decision.

The Solution

First, see the hiring decision for what it really is. Hiring isn't a process to be completed as quickly and efficiently as possible.

Deciding whom to hire, especially for a small business, is an incredibly important decision -- one that deserves considerable thought, analysis, and consideration.

And one that is too important to allow to fall prey to cognitive and social biases.

So take a page from the Jeff Bezos meeting playbook. Once the interviews are complete, require each member of the hiring team to write a memo describing their findings: Strengths and weaknesses of each candidate, perceived cultural fit, the reasoning behind their analysis, and so on.

Require each person to communicate, in writing, the thoughts behind their assessments and judgments.

Then it's much harder for people to wing it during the meeting. And it's much harder for people to rely on force of personality or relative organizational status to overcome a lack of thought and preparation.

Next, start the meeting with silence while everyone on the hiring team reads one another's memos. That way everyone can benefit from each other's full insights, rather than their summary opinions.

And that way it will be obvious who did and did not do their homework -- and therefore, whose summary opinions should carry more weight.

Then discuss.

While one of you will still have to go first, the subsequent discussion will be more likely to focus on each candidate's relative experiences, qualifications, achievements, and fit. 

Not by the order in which opinions are shared. Or by whether the first opinion was positive or negative.

Or by a process that makes agreeing on a decision seem more important than making the best decision.