If you can bolster testimonies with hard numbers and facts, you’ll be more effective as a speaker. Scientific research findings carry a lot of weight with audiences, particularly if your topic is related to medicine, health, media, or the environment. For example, in a speech about educational television programs, a speaker might point out that studies have found that children who watched Sesame Street as preschoolers were more likely to enjoy elementary school and to achieve higher grades even in high school (Huston & Wright, 1998).

Statistics—information provided in numerical form—can also provide powerful support for a speech, sometimes more than words. Statistics reveal trends, explain the size of something, or illustrate relationships. They can be made more meaningful when paired with or made part of factual statements—truthful, realistic accounts based on actual people, places, events, or dates. For example, when speaking about domestic violence, you might use a combination of statistics and factual statements to back your statement that a person is more likely to be killed by a family member or close acquaintance than a stranger:

Out of 13,636 murders studied in the United States, 30.2% of the victims were murdered by persons known to them (4,119 victims), 13.6% were murdered by family members (1,855 victims), 12.3% were murdered by strangers (1,676 victims), and 43.9% of the relationships were unknown (investigators were not able to establish any relationship). (U.S. Department of Justice, 2010)

Although accuracy is important, we must note that specific numbers and percentages are cumbersome to speak aloud and can be easily forgotten by your audience. Remember that your visual aids can give the specifics while you round numbers and percentages aloud.