Most people think that the negotiation is about substance: I’m a financial expert, I’m a medical doctor, I’m an environmental lawyer, I’m an energy expert, I’m a mechanic. But studies show that less than 10 percent of the reason why people reach agreement has anything to do with the substance. More than 50 percent has to do with the people—do they like each other, do they trust each other, will they hear what each other has to say? Just over a third has to do with the process they use. That is, do they decide to explore each other’s needs (rational and emotional)? Do they agree on an agenda? Do they make genuine commitments to each other?

If you believe that negotiations are about the substantive issues, sadly, you will be right more than you are persuasive. That means that the truth, the facts, are only one argument in a negotiation. The people and the process are much more important. This is particularly hard for people who are focused on the substance—doctors, engineers, financial experts—to accept. But, based on research, it is true. You can’t even use substantive issues to persuade effectively unless and until the other party is ready to hear about them.

--Stuart Diamond, Getting More, 2010, pp. 51-52