The negotiation classic Getting to Yes describes a system of interest-driven negotiation by way of contrast to more common “positional bargaining.” Unfortunately, positional bargaining is so common that many people believe it is the essence of negotiation itself.

You already know what positional bargaining is, even if you don’t know it by that name. James, who wishes to sell his motorcycle, initially asks for $ 3,000. But this is more than he really expects to get. He exaggerates his initial position in order to have room for compromise. In his mind, he has established a lower “bottom line” that is as low as James is willing to go. Similarly, Bob, who’s in the market for a motorcycle, initially makes a lowball offer of $1,000 for James’s bike, but has in mind a “top line,” which is as high as Bob is willing to go.

My own term for positional bargaining is “number line tug-of-war.” You can imagine James standing on a giant number line at the $3,000 mark and Bob standing on the same number line at $1,000. Now each tries to tug the other closer to himself, while minimizing his own moves along the number line. Positional bargaining, or number line tug-of-war, is founded on the principle of compromise. Each person assumes that he and his counterpart must, and will, give in on their opening positions.

If James’s bottom line is $1,500, and Bill’s top line is $2,500, they may compromise at about $2,000. But if James’s bottom line is $2,500, and Bill’s top line is $1,500, and if they remain true to their respective bottom and top lines as the test for whether or not to enter into an agreement, they will not make a deal.

As Getting to Yes points out, bottom lines and top lines are not the best tests for whether or not one should enter into an agreement. This is where the interests in interest-driven negotiation come in. Instead of taking initial positions, the two negotiators explore their true interests. Suppose James’s reason for selling his bike is that he wants to use the proceeds from the sale to purchase an above-ground pool for his backyard. Getting a pool is his real interest.

What if Bill has a pool he no longer wants? In this case, the numerical bottom and top lines were not helpful guides. Both men might have made a better deal by simply trading the motorcycle for the pool.

A better guide would be what Getting to Yes calls a “BATNA.” This acronym stands for “best alternative to a negotiated agreement.” Two of the reasons the term is misunderstood are that people find it hard to remember what the acronym stands for, and even when they do remember it, its abstract nature makes it difficult to understand. So in my writings and training courses, I’ve coined the term “walkaway alternative.”

What is the very best thing James can do to satisfy his true interest if he can’t make a deal with Bill. In other words, what will he do if he has to walk away from the negotiation table? That is James’s walkaway alternative.

James may decide that his best walkaway alternative is to wait until he can find a buyer who will pay enough for his motorcycle to enable him to get the pool he wants. Or he may do some Internet research, learn that motorcycles like his, and in similar condition, usually don’t bring enough to purchase the kind of pool he wants, and so decide that his best walkaway alternative is to take a temporary, part-time job to earn the money to buy the pool. Or he may decide that he would like to swim in all kinds of weather, so instead of buying a pool, he will join a club, which has the added advantage of not having to come up with a large amount of money all at once.

Whatever James decides is the best walkaway alternative for him, he then negotiates with Bill to determine the best price Bill is willing to pay for the motorcycle. James compares that price to his best walkaway alternative. If Bill’s offer satisfies James’s interest better than his best walkaway alternative, he accepts Bill’s offer. But if Bill’s best offer does not satisfy James’s interest as well as his best walkaway alternative, he walks away from the negotiating table and executes his walkaway alternative.

It would make my dentist very happy if everyone who tosses around the term BATNA really understood what it means, for I sometimes hear people use the term to mean the exact opposite. Some People use it to mean a bottom line, but in fact, it means a different, and better, alternative to a bottom line. And when I hear BATNA used to refer to a bottom line, I want to grind my teeth.

In fairness, even under my more evocative name “walkaway alternative,” the concept is abstract, complex, and thus, more difficult to understand, then the simple concept of the bottom line. But I assure you that understanding it is worth the effort. Once you grasp this test for whether or not to enter into an agreement, you will feel more confident of your decisions and will make better deals when you do enter an agreement.