How to Write an Expository Essay

How to Plan, Structure, and Write Up Your Information

Encyclopedia Brittanica on a bookshelf
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Expository writing is used to convey information. It is the language of learning and understanding the world around us. If you've ever read an encyclopedia entry, a how-to article on a website, or a chapter in a textbook, then you've encountered a few examples of expository writing.

Types of Expository Writing

In composition studies, expository writing (also called exposition) is one of the four traditional modes of discourse. It may include elements of narrationdescription, and argumentation. Unlike creative or persuasive writing, which can appeal to emotions and use anecdotes, expository writing's primary purpose is to deliver information about an issue, subject, method, or idea using facts. Exposition may take one of several forms:

  • Descriptive/definition: In this style of writing, topics are defined by characteristics, traits, and examples. An encyclopedia entry is a kind of descriptive essay. 
  • Process/sequential: This essay outlines a series of steps needed in order to complete a task or produce something. A recipe at the end of an article in a food magazine is one example.
  • Comparative/contrast: This kind of exposition is used to demonstrate how two or more subjects are the same and different. An article that explains the difference between owning and renting a home and the benefits and drawbacks of each is one such an example.
  • Cause/effect: This kind of essay describes how one step leads to a result. An example is a personal blog chronicling a workout regimen and documenting the results over time.
  • Problem/solution: This type of essay presents a problem and possible solutions, backed by data and facts, not just opinion.
  • Classification: A classification essay breaks down a broad topic into categories or groupings.

Planning Your Essay

  1. Brainstorm. Jot down ideas on a blank piece of paper. Connect them with arrows and lines, or just make lists. Rigor doesn't matter at this stage. Bad ideas don't matter at this stage. Just write down ideas, and the engine in your head will lead you to a good one.
    When you've got that idea, then repeat the brainstorming exercise with ideas that you want to pursue on that topic and information you could put in. From this list, you'll start to see a path emerge for your research or narrative to follow.
  2. Write your thesis sentence. Examine it. Is it too narrow or too broad to be covered in the amount of space you have for your paper? If so, refine it. Don't be dismayed if you have to come back and tweak it if your research finds that your initial idea was off-kilter. It's all just part of the process of focusing the material.
  3. Outline. It may seem inconsequential, but making even a quick outline can save you time by organizing your areas of pursuit and narrowing them down. When you see your topics in an organized list, you may be able to discard off-topic threads before you research them—or as you're researching them and you find they just don't work.
  1. Research. Find your data and sources to back up the areas you want to pursue to support your thesis statement. Look for sources written by experts, including organizations, and watch for bias.

Structuring an Expository Essay

An expository essay has three basic parts: the introduction, the body, and the conclusion. Each is crucial to writing a clear article or effective argument.

The introduction: The first paragraph is where you'll lay the foundation for your essay and give the reader an overview of your thesis. Use your opening sentence to get the reader's attention, and then follow up with a few sentences that give your reader some context for the information you're about to cover.

The body: At a minimum, you want to include three to five paragraphs in the body of your expository essay. The body could be considerably longer, depending on your topic and audience. Each paragraph begins with a topic sentence where you state your case or objective. Each topic sentence supports your overall thesis statement. Then, each paragraph includes several sentences that expand on the information and/or support the topic sentence. Finally, a concluding sentence offers a transition to the following paragraph in the essay.

The conclusion: The final section of your expository essay should give the reader a concise overview of your thesis. The intent is not merely to summarize your argument but to use it as a means of proposing further action, offering a solution, or posing new questions to explore. Don't cover new material related to your thesis, though. This is where you wrap it all up.

Tips for Expository Writing

As you write, keep in mind some of these tips for creating an effective expository essay:

Start where you know the information best. You don't have to write your introduction first. In fact, it might be easier to wait until the end for that. If you don't like the look of a blank page, move over the slugs from your outline for the main body paragraphs and write the topic sentences for each. Then start putting in your information according to each paragraph's topic.

Be clear and concise. Readers have a limited attention span. Make your case succinctly in language that the average reader can understand. 

Stick to the facts. Although an exposition can be persuasive, it should not be based on opinion only. Support your case with facts, data, and reputable sources that can be documented and verified.

Consider voice and tone. How you address the reader depends on the kind of essay you're writing. An essay written in the first person is fine for a personal travel essay but is inappropriate if you're a business reporter describing a patent lawsuit. Think about your audience before you begin writing.