Writing Mini-Lessons: Thesis Statements (or Theses)

A thesis statement in an essay is a sentence that explicitly identifies the purpose of the paper or previews its main ideas.

A thesis statement is an assertion, not a statement of fact or an observation.

  • Fact or observation: People use many lawn chemicals.
  • Thesis: People are poisoning the environment with chemicals merely to keep their lawns clean.


A thesis takes a stand rather than announcing a subject.

  • Announcement: The thesis of this paper is the difficulty of solving our environmental problems.
  • Thesis: Solving our environmental problems is more difficult than many environmentalists believe.


A thesis is the main idea, not the title. It must be a complete sentence that explains in some detail what you expect to write about.

  • Title: Social Security and Old Age.
  • Thesis: Continuing changes in the Social Security System makes it almost impossible to plan intelligently for one’s retirement.


A thesis statement is narrow, rather than broad. If the thesis statement is sufficiently narrow, it can be fully supported.

  • Broad: The American steel industry has many problems.
  • Narrow: The primary problem if the American steel industry is the lack of funds to renovate outdated plants and equipment.


A thesis statement is specific rather than vague or general.

  • Vague: Hemingway’s war stories are very good.
  • Specific: Hemingway’s stories helped create a new prose style by employing extensive dialogue, shorter sentences, and strong words.


A thesis statement has one main point rather than several main points. More than one point may be too difficult for the reader to understand and the writer to support.

  • More than one main point: Stephen Hawking’s physical disability has not prevented him from becoming a world-renowned physicist, and his book is the subject of a movie.
  • One Main point: Stephen Hawking’s physical disability has not prevented him from becoming a world renowned physicist.


You can revise your thesis statement whenever you want to while you are writing your essay. Writers often discover what their real purpose and point is in the process of putting their thoughts into words and then reading what they’ve written.

Remember this:  Claim + Reason = Thesis

For even more information about writing thesis statements, check out Purdue OWL.