A thesis statement is a single sentence that declares the main purpose of the entire essay, answering the question, “What is my opinion?” or “What will I illustrate, define, analyze or argue in this essay?” The thesis statement helps the writer stay focused while writing and sets the reader’s expectations for the essay. Here is a brief overview:

The Working Thesis Statement

Thesis statements don’t spring fully formed from the head of Zeus (look it up!); they develop naturally during the writing process. Once you have a pretty solid idea of the topic you are going to write about, sketch out a tentative, or working, thesis statement to help guide your writing. Some students like to write this controlling sentence on a 3x5 inch card and keep it next to the computer as they write their draft to prevent going off topic.

This working thesis statement is not written in stone. As you research, think, write, and revise, you will discover that your subject needs to be narrowed or expanded, or you will discover nuances that need to be accounted for. That’s fine! With each discovery, you should tweak and adjust the thesis statement so that it says precisely what you mean to say and prepares readers for what you are going to tell them.

Examples

Drafting a thesis statement that is neither too broad nor too narrow can be a challenge. Consider the following thesis statements, one set for each of the three categories of essay:

INFORMATIVE

• Too Specific: Some planarians have two eye-spots, while others have several.
  (Interesting fact, briefly informative, but what else can be said?)
• Too General: Planarians are cool!
  (It’s an enthusiastic statement but also vague and broad.)
• Just Right: Planarians’ wide distribution, simple physical characteristics, and interesting life cycle make them ideal research subjects.
  (The subject has been limited to three substantial points to explain or describe.)

ANALYTICAL

• Too Specific: In The Great Gatsby, F. Scott Fitzgerald follows the residents of fictional Long Island towns West Egg and East Egg.
  (This is a true statement but leaves no room for analysis.)
• Too General: Throughout The Great Gatsby, F. Scott Fitzgerald explores many themes.
  (This thesis statement implies the essay will analyze multiple themes; how can anyone possibly analyze all that in one essay?)
• Just Right: Despite their class differences, each character in F. Scott Fitzgerald’s The Great Gatsby strives to achieve their version of the American Dream.
  (Because it is limited to one topic, there is plenty of room for analysis here.)

ARGUMENTATIVE

• Too Specific: My cousin saved a lot of money on his insurance plan because of the Affordable Care Act.
  (Not actually an arguable statement: either he did or did not save. Besides, after stating how much he saved, that’s about it for this topic.)
• Too General: Serious changes should be made to the Affordable Care Act.
  (This statement is vague: what direction will we be going with these changes—improving it, replacing it, or simply overturning it?)
• Just Right: While it’s a major step in the right direction, the Affordable Care Act should include a single-payer option in order to most effectively meet the needs of all US citizens.
  (This statement predicts the essay will argue both that the ACA is a step in the right direction and that the single-payer option would be the best choice for improving it, both arguable and limited ideas.)

Polishing the Thesis Statement

Once you have completed a draft of your paper, reassess the thesis statement to make sure it is strong and clear and covers everything in the draft. If it does not, add whatever has been left out in the thesis; it is easier to adjust the thesis statement than to rewrite the whole essay, and if you have been adjusting the thesis statement all during the process, it should be very close.

Where Does It Go?

The thesis statement is seldom the very first sentence of an essay. In most academic writing, it will be most effective at the end of the introductory paragraph. This allows you to introduce the subject, hook the reader, and/or give background before stating the purpose of the essay. At this point, readers will be ready for whatever you’re going to tell them, creating a natural transition from the introduction to the body.

For other thesis statement placement options, see “Induction vs. Deduction.”