You may have a brilliant new business strategy, but unless employees are stoked about the idea, it won't succeed, says leadership guru John P. Kotter, a Harvard Business School professor and author of several books on organizational change. Kotter's new book, Buy-In (Harvard Business Press), promotes a counterintuitive way to build support for a new idea: by encouraging employees to criticize it. If you are good at playing defense, Kotter reasons, you will win employees over. In the book, Kotter and co-author Lorne A. Whitehead teach CEOs how to deflect common criticisms, including comments like, "If this is such a great idea, why hasn't anyone done it already?" Senior editor Bobbie Gossage spoke with Kotter about this strategy.

Why is buy-in important?

Seventy percent of major change efforts either don't get started or fail. If you look at the most successful cases -- the top 5 percent of leaders who actually made something terrific happen -- they were very good at communicating in a way that won people over.

In your book, you say it's important to invite criticism of your idea. Why is that helpful?

Modern life is an information overload. The single biggest problem in trying to make big changes is simply getting people's attention. One of the most effective ways of doing that is to invite people to throw rocks at you. It causes sparks. Sparks grab our attention.

Isn't there a danger in that?

Sure, if you don't know how to deal with it. We all go into fear mode if we're afraid we're going to be embarrassed or hurt. Or we'll get mad, because people are attacking something we care about and think is right. That's why it's important to know how to respond to these generic attacks.

What is the most common attack?

The ultimate is always: We've been successful -- why change? People will say something like, "We've been doing terrific with our current strategy for years. Nothing against the new idea, Boss, but isn't it risky to change something that works so well?" That one comes up almost every time somebody is trying to sell a new idea. The most effective response to that is: Life evolves, and to continue to succeed, we must adapt.

Most of the responses you suggest in the book are surprisingly brief.

When someone attacks our idea, we've been taught to drill down and give the 16 reasons why it is good. If we've worked hard on something and believe in it, we know 16 reasons -- or even 116 reasons -- why it's a good idea. But after somebody lists the 43rd reason, people just tune out. The most effective counterstrategy seems to be simple, commonsense answers that don't drag you into quicksand.

It almost seems as if you have to think like a politician.

Maybe a good politician. But these are not spins. That's what makes us all mad about politics. Someone throws out a question, and the guy doesn't answer it, or he outright lies. These are honest, direct, commonsense responses.

Is it natural to avoid criticism?

Most CEOs are very cautious about walking into public forums and making it easy for someone to stand up and attack their idea. If you go around to employees and make 19 speeches in a setting where it's hard to ask tough questions, it feels as though you are spending a lot of time communicating this strategy. And you see people's heads nodding, so they must be buying in, right? But you walk away with a total misreading of the situation.

If you go back to those same people a month later and ask them to explain what was said in that meeting, they can't. And the first time that person is put in a position where he or she needs to do extra duty to make that strategy a reality, it doesn't happen, because there's no emotional energy behind it.

So how can you tell if employees have truly bought in?

You make yourself accessible. You ask questions and don't just make speeches. You give off signals, verbal and nonverbal, that you are interested. This isn't just, "Tell me what you think I want to hear."

Often CEOs don't want to hear employees say, "I don't get it" or "I don't believe it." They have a mindset of, Let's go! The competition is coming at us, and the window of opportunity is closing! It's easy to let yourself believe that people have bought in when they haven't.