So you can't completely trust your colleagues? When you're talking to second opinions, it's very hard to sort out what people are saying in their own self-interest and what they're saying that's really objective. I'm not talking about bad and devious people. We're all organizational people, and it's not wise in organizational life to always tell the unvarnished truth.

Also, in an organization, you build strong cultures of belief that bind people together and allow them to do extraordinary things. The only problem with that is that every strong culture has a way of looking at the world that leaves things out. I worked at Microsoft, and Microsoft looks at the world through a very Microsoft-centric lens. When you're there, that's very compelling, but it isn't the whole picture.

How do you find third-opinion advisors? One of the most important functions of networking is to meet interesting thinkers who can bring perspective and insight to your work. First, look for people who have the ability to see multiple sides of a complex issue. Second, look for someone who asks great questions and listens for what isn't said as much as to what is said. Obviously, you absolutely have to have someone of the highest integrity. They have to have useful expertise and knowledge. And this sounds contradictory, but I look for people who don't offer advice.

But aren't you going to them for advice? It isn't about them saying, "Oh, I've listened to you, here's what I would do." It's about their ability to explore with you the complexities of a situation until it becomes clear to you what makes sense for you to do.

Now that you have your third-opinion people, how do you know which issues require their input? Very often, leaders I'm working with have to make a choice: Am I going to buy or sell a business; am I going to put more resources into building a certain part of my business and take them away from something else? They've looked at it themselves and they have a great team and they have tons of data. But the reality is that every single choice has positives and negatives. A great place for third-opinion work is to help people look at unintended consequences … that will clearly make one choice better than another.

How many third opinions should people solicit? When you do it well, it's a network. A senior leader will generally have two or three people.

Some people find one person they're really great with, and they  latch on - which is great, but it has some problems. For instance, if you're only talking to one person, over time that can become habitual.

What do you do if your colleagues are telling you one thing and your third opinion is telling you something completely opposite? The goal of the third opinion is to help you broaden your own thinking. The last thing you do is walk in and say, "Well, guys, you've all been telling me this, but I've been talking to Saj-nicole and she says this, and I'm going with her. "That's a recipe for disaster. Great leaders know how to take their teams through a process similar to the one they've been through with their third-opinion advisors.