Presenting proof makes a powerful presentation. But proof alone rarely makes a sale. Or sells an idea. Many people have wasted enormous amounts of time gathering proof only to discover that a prospect or a manager wouldn't agree that their data proved anything. Always agree on what the other party accepts as proof.

Next, confirm that the other party considers such proof meaningful. For example, you may prove that your engine is faster than any on the market, but if your client values low-cost maintenance more than speed, your proof will be "beside the point."

Then document your proof in writing so others can verify it. It's always advisable to capture your data and publish it in an article or white paper so that it passes the scrutiny of all concerned.

Finally, don't build your whole presentation around your proof, counting on it as "the sure thing." People buy for any number of reasons, and logical proof is only one of them.