What Is a Thesis Statement?

Some teachers might call it an argumentative paper; others might call it a persuasive paper. But if you're taking a position on a topic and must present a claim – an assertion – and back it up with evidence, facts and statistics, there is no way around writing a thesis statement. Many forms of essays – including cause-effect, comparison-contrast, definition, descriptive, example, narrative and process essays – also include a thesis statement. You're bound to get a lot of practice writing thesis statements, but first you must understand what they are and how vital they are to any type of paper you might write.

A thesis statement is a one-sentence summation of a paper's purpose and direction. It almost always appears at the end of a short introduction. At this pivotal juncture, it's then your job as a writer to prove, support and defend your thesis statement throughout your paper. Everything that follows the thesis statement -- every paragraph and even every sentence -- should amplify and elaborate upon the thesis statement. In this way, your thesis statement serves as a compass; it should keep you on track with your research and writing and prevent you from veering off on tangents and irrelevant points.

A thesis statement in an argumentative or persuasive paper often contains “a should” statement, as in, “Texting should be outlawed in all U.S. states to reduce the growing number of accidents that occur each year when people attempt to multi-task as they drive.” A thesis statement in an essay also might contain a “should” statement, or it might be more subtle, as in a descriptive essay in which a writer describes the importance of daily family dinners: “While I thought my mother made a federal case about it then, today I realize that sharing dinner together with my family every night was the best way to communicate and stay close to the people I care about most.” Imagine a reader sizing up either thesis statement and saying, “Really? Tell me more; prove your point.” An effective thesis statement sets an expectation; as a writer, it's your job to fulfill it.