Mark Twain attributed the statement that, in politics there are “lies, damned lies, and statistics” to the British politician Benjamin Disraeli. It is true that statistics can be used to distort or confuse, but they are also useful, if used well, in enhancing your speeches.
First of all, statistics add realism to your speech. They give a concrete example on which your audience can anchor their understanding. These are not mere anecdotes, but factual data which can clarify the picture.
Statistics can stick with your audience. Solid round numbers are easily remembered and “taken away” by your hearers, where more complex arguments may have a more limited retention rate. After all “9 out of 10 dentists” or “70% of cat owners” are catchy phrases.
Statistics can also have an emotional impact or pathos on your audience. Large figures or percentages can have a “shock” value. They elicit an emotional response, because they can “proclaim” inequality (e.g. the number of homeless in an area) or illustrate burden (e.g. the rise in taxation rates).
Statistics raise your credibility, in that they suggest you have “done your homework.”
Statistics can also make appeals to authorities greater than your own, to support your views. By quoting figures you are inferring the authority of the studies cited, and the expertise of the compilers of the data.
Be warned however, too many statistics can, like too many chefs, “spoil the broth.” Use them sparingly, strategically, and thoughtfully.