Facts are seemingly reassuring. They back our assertions and give us ground to stand on. Worried speakers gather them for many reasons, not realizing abundance is harmful to a speech, because it's a lot easier to compile data than to make them interesting. Some speakers use facts to back up their claims, thinking that the more information the audience gets, the more believable and compelling the speech will be. They use facts to give speeches an objective—and therefore a powerful—tone. Other speakers feel the audience needs to know a lot and pile facts and lists into a speech in an attempt to give people their "money's worth."
However well intentioned, both approaches are misguided and work against both the speaker and the audience. Audience overload occurs surprisingly quickly. People retain three or four main points—nicely illustrated and explained—better than they do myriad bits of supporting information. Instead of bolstering your audience, excess facts just bog the audience down.
But the fact problem goes even deeper. An abundance of data is not the best support for your argument. Anyone can read a list of facts; your job is to make that information interesting, to give your viewpoint, using your own style and voice. Audiences don't want sheer objectivity: They want your interpretation.
Remember that you have been invited to speak for reasons that have nothing to do with your research abilities. You have something unique to say on the subject, some special angle.
My first job was teaching very bright high-school kids. I was a nervous wreck, because I figured that they were so much smarter than I was, which was undoubtedly true. I studied and studied before each class and ran a losing battle trying to stay ahead of them.
At the time, I didn't realize that I knew enough about the subject; I already had enough information. What I needed to do was make that information interesting and meaningful to students. They may have had more intelligence, but I had the experience to translate the facts vividly. Once I realized they were there to hear my interpretation of the subject, I was fine.