Most readers want more than a thesis statement — they want to know why they should accept it. If readers who are thinking about purchasing a car come across a thesis statement such as “For many drivers, renting a car on an occasional basis is a cost-effective alternative to owning one,” they’ll want to know why renting could be a better choice. If readers interested in financing a college education read a thesis statement such as “Today’s college students have a wide range of options for reducing the overall cost of a college education,” they’ll want to know what those options are. To convince readers to accept your thesis statement, you’ll need to provide supporting points and offer evidence for each point.
Choose your supporting points. Supporting points are the reasons you give readers to accept your main point. They are usually expressed as topic sentences in the form of general statements, such as “Renting a car means you can pay less in car insurance” or “If your family qualifies, Pell Grants can significantly reduce the cost of a college education.” Consider, for instance, the way George Chauncey presents the supporting points for his essay about discrimination against gay and lesbian Americans. Each paragraph opens with a clearly stated topic sentence (“Fifty years ago . . .”) that identifies a form of discrimination from the past. As you choose your supporting points, keep in mind that not only should they serve as reasons to accept your main point but they should also be consistent with how you’ve presented your thesis statement. In short, you should resist the urge to include every idea you’ve come across. You can find more advice on developing support for a thesis statement in Chapter 14.
Identify evidence for each supporting point. Without evidence to support them, even the most clearly expressed supporting points will not be enough to inform your readers fully. You need evidence to help them understand why they should accept the reasons you’ve used to support your thesis statement. In a profile of Temple Grandin, for instance, the author used evidence to illustrate a point about Grandin’s contribution to animal welfare in the livestock industry:
Today, at least half of all cattle in the United States and Canada, as well as many in other countries, are handled in humane slaughter systems designed by Grandin. Her animal welfare guidelines have become the gold standard in the $80 billion meat-packing industry.
Writers of informative essays also use information from sources to present ideas and clarify statements. You might define a concept by quoting from an interview, paraphrasing an article, or summarizing a report. You might amplify a statement by providing examples from sources. Or you might qualify a statement by noting that it applies only to specific situations and then use a quotation or paraphrase from a source to back that up, as George Chauncey does in his essay about discrimination against gay and lesbian Americans:
The absolute ban on gay representation, vigorously enforced by Hollywood’s own censorship board, remained in effect for some thirty years and effectively prohibited the discussion of homosexuality in the most important medium of the mid-twentieth century, even though some filmmakers found subtle ways to subvert it.
As you select information from sources for your essay, consider your writing situation. Be sure that the evidence you choose will help you accomplish your purpose; that you provide enough detail and explanation to help readers understand the information, ideas, or arguments you present to them; and that you can present the evidence in a way that won’t conflict with your readers’ values and beliefs.
To identify evidence to support your points, follow these guidelines: