What Is a Thesis Statement?

A thesis statement is a single sentence — usually the last sentence of your introduction — that presents your paper's central argument or claim. It tells the reader what you are arguing and why it matters. Every paragraph in your paper should support and relate back to this statement.

The Three Requirements of a Strong Thesis

1. It must be arguable. A good thesis makes a claim that a reasonable person could disagree with. "World War II caused significant suffering" is not a thesis — it is an obvious fact. "The Allied bombing campaign in World War II, while militarily effective, constituted a deliberate targeting of civilian morale that raises serious ethical questions under modern just war theory" is arguable.

2. It must be specific. Vague theses produce vague papers. "Social media is bad for teenagers" is too broad. "Instagram's algorithmic promotion of appearance-based content is directly correlated with increased rates of body dysmorphia and depression among adolescent girls, warranting regulatory intervention."

3. It must be provable with evidence. Your thesis should be supportable through research, data, examples, or logical reasoning — not just personal opinion.

The Formula

A reliable formula: [Specific topic] + [Your position/claim] + [3 main reasons or "because" clause]

Example: "Remote work policies should be made permanent at large corporations because they increase employee productivity, reduce overhead costs, and demonstrably improve work-life balance outcomes as measured by turnover rates."

Common Mistakes

  • Announcing intention: "This essay will argue that..."
  • Stating a fact instead of a claim
  • Being too broad or too narrow
  • Placing the thesis anywhere other than the end of the introduction
  • Forgetting to update the thesis after writing the paper