OWL at Purdue University: Writing a Thesis Statement

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Writing a Thesis Statement

A thesis statement is a sentence (or sentences) that expresses the main ideas of your paper and answers the question or questions posed by your paper. It offers your readers a quick and easy to follow summary of what the paper will be discussing and what you as a writer are setting out to tell them. The kind of thesis that your paper will have will depend on the purpose of your writing. This handout will cover general thesis statement tips, explain some of the different types of thesis statements, and provide some links to other resources about writing thesis statements.

General Thesis Statement Tips

A thesis statement generally consists of two parts: your topic, and then the analysis, explanation(s), or assertion(s) that you're making about the topic. The kind of thesis statement you write will depend on what kind of paper you're writing.
In some kinds of writing, such as narratives or descriptions, a thesis statement is less important, but you may still want to provide some kind of statement in your first paragraph that helps to guide your reader through your paper.
A thesis statement is a very specific statement -- it should cover only what you want to discuss in your paper, and be supported with specific evidence. The scope of your paper will be determined by the length of your paper and any other requirements that might be in place.
Generally, a thesis statement appears at the end of the first paragraph of an essay, so that readers will have a clear idea of what to expect as they read.
You can think of your thesis as a map or a guide both for yourself and your audience, so it might be helpful to draw a chart or picture of your ideas and how they're connected to help you get started.
As you write and revise your paper, it's okay to change your thesis statement -- sometimes you don't discover what you really want to say about a topic until you've started (or finished) writing! Just make sure that your "final" thesis statement accurately shows what will happen in your paper.

Analytical Thesis Statements

In an analytical paper, you are breaking down an issue or an idea into its component parts, evaluating the issue or idea, and presenting this breakdown and evaluation to your audience. An analytical thesis statement will explain:

what you are analyzing
the parts of your analysis
the order in which you will be presenting your analysis

Example: An analysis of barn owl flight behavior reveals two kinds of flight patterns: patterns related to hunting prey and patterns related to courtship.

A reader who encountered that thesis in a paper would expect an explanation of the analysis of barn owl flight behavior, and then an explanation of the two kinds of flight patterns.

Questions to ask yourself when writing an analytical thesis statement:

What did I analyze?
What did I discover in my analysis?
How can I categorize my discoveries?
In what order should I present my discoveries?

Expository (Explanatory) Thesis Statements

In an expository paper, you are explaining something to your audience. An expository thesis statement will tell your audience:

what you are going to explain to them
the categories you are using to organize your explanation
the order in which you will be presenting your categories

Example: The lifestyles of barn owls include hunting for insects and animals, building nests, and raising their young.

A reader who encountered that thesis would expect the paper to explain how barn owls hunt for insects, build nests, and raise young.

Questions to ask yourself when writing an expository thesis statement:

What am I trying to explain?
How can I categorize my explanation into different parts?
In what order should I present the different parts of my explanation?

Argumentative Thesis Statements

In an argumentative paper, you are making a claim about a topic and justifying this claim with reasons and evidence. This claim could be an opinion, a policy proposal, an evaluation, a cause-and-effect statement, or an interpretation. However, this claim must be a statement that people could possibly disagree with, because the goal of your paper is to convince your audience that your claim is true based on your presentation of your reasons and evidence. An argumentative thesis statement will tell your audience:

your claim or assertion
the reasons/evidence that support this claim
the order in which you will be presenting your reasons and evidence

Example: Barn owls' nests should not be eliminated from barns because barn owls help farmers by eliminating insect and rodent pests.

A reader who encountered this thesis would expect to be presented with an argument and evidence that farmers should not get rid of barn owls when they find them nesting in their barns.

Questions to ask yourself when writing an argumentative thesis statement:

What is my claim or assertion?
What are the reasons I have to support my claim or assertion?
In what order should I present my reasons?

Further Resources

For more about writing an argumentative paper, you might want to visit our research paper workshop, which covers writing research papers from start to finish.

Many writing centers and writing websites offer help with writing thesis statements. Here are some links to get you started.

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This handout written by Erin Karper, August 2002

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