What is a Central Idea?
Make The Central Idea The Focus of Your Writing
Begin with a Working Topic Sentence or Thesis
What is my Subject?
What is my Purpose?
What is my Main Point?
Check Your Working Central Idea
A Central Idea is Specific
A Central Idea Contains A Main Point That is Worth Developing
A Central Idea is Limited
Limit the Discussion to a Manageable Length
Limiting Your Central Idea Further
Differences Between a Topic Sentence and A Thesis
Revise and Refine the Central Idea as You Work

THE CENTRAL IDEA: DRAFTING A TOPIC SENTENCE OR THESIS STATEMENT

WHAT IS A CENTRAL IDEA?

The central idea holds your writing together. In a paragraph, the central idea is expressed in a topic sentence. In an essay, it is expressed in a thesis statement. The central idea is the idea your paragraph or essay develops, supports, or proves.

MAKE THE CENTRAL IDEA THE FOCUS OF YOUR WRITING

The central idea states the point you wish to make. It is the focal point to which all details in your essay point. Think of a paragraph or essay as a photograph. Just as you focus a snapshot by aiming the camera at a fixed point, you focus your writing by relating every detail to a central idea.

You can also compare the central idea to an umbrella. Expressed as a thesis statement (essay) or in a topic sentence (paragraph), the central idea will be the broadest or most general statement in your work. All other ideas and bits of information fit logically under the central idea.

BEGIN WITH A WORKING TOPIC SENTENCE OR THESIS

A working topic sentence or thesis is your first attempt to express a central idea formally. You will probably revise it many times as you write drafts and discover exactly what to say about your subject. Writing a working topic sentence or thesis statement involves three steps:

• Choosing a subject to write about.
• Deciding what point to make about the subject.
• Testing your central idea for qualities that will make it effective as the basis of a paragraph or essay.

Back to Top

WHAT IS MY SUBJECT?

A subject is abstract, general, and incomplete. A central idea is concrete and specific. Compare the subject cigarette smoking with the central idea Cigarette smoking is expensive, harmful, and offensive.

You can turn a subject into a central idea by focusing. Begin by reviewing what you know about your subject or by looking over notes you have made about it through listing, brainstorming, clustering, freewriting, or other prewriting activities.

With these details fresh in your mind, ask yourself:

What is my purpose in writing about this topic?
What main point do I want to make about the topic?

WHAT IS MY PURPOSE?

Let's say you decide to write about high school. You might tell a story about your history class, compare two schools you attended, or argue that high schools should require foreign-language study.

If you want to compare the two high schools you attended, you can include details about their academic programs, athletic teams, students, or teachers. But you probably wouldn't argue that high schools should stay open in summer because doing so would take you outside your declared purpose.

WHAT IS MY MAIN POINT?

The next step in focusing is to decide what to say about your subject. What is the most interesting or important point you want to make about the schools you are comparing? The answer will be your main point, which ties all the details of the essay together.

Again, you turn an abstract subject into a central idea by stating a main point about that subject. If your main point is that entering a new school improved your attitude about education, your central idea might read:

Changing high schoolsmade me a more serious student.

MAKING A POINT ABOUT A SUBJECT

In the box below, main points have been added to subjects to form working topic sentences or thesis statements.

Back to Top

CHECK YOUR WORKING CENTRAL IDEA

After writing a working central idea, check it for qualities that will make it effective as the basis of a paragraph or essay. Ask yourself:

Is my central idea expressed in a complete thought?
Is it specific?
Does it express an idea that is worth developing in a full-length paragraph or essay?
Is it limited enough to discuss in a short piece of writing?

Never confuse a central idea with a simple subject. Central ideas are expressed in complete sentences; subjects are words or phrases. Take these subjects:

The city zoo.
Professional athletes.
Majoring in foreign languages.

Can you write a paragraph or essay on one of these subjects? Only if you decide on the main point you want to make about it. Try these as working central ideas:

The city zoo is in great need of repairs.
Professional athletes are overpaid.
Studying foreign languages leads to many career choices.

A CENTRAL IDEA IS SPECIFIC

Make your central idea specific. The key to this step is to focus your main point as precisely as you can. That will give you a clear direction to follow as you develop an essay or paragraph. Take this central idea:

Jogging isn't for everybody.

It is correct, but it leaves questions unanswered. For example, what kind of people should not jog? What ill effects might jogging cause them? Now, try this:

Jogging can be harmful to people who suffer from heart, back, or joint problems.

A CENTRAL IDEA CONTAINS A MAIN POINT THAT IS WORTH DEVELOPING

Make sure your main point is an idea-not just a fact-that is worth developing in a full-length paragraph or essay. Read these two sentences:

The War Memorial is in Ottawa.
The War Memorial has been severely vandalized.

The first sentence is a statement of fact; it does not call for discussion. The second lends itself to discussion. For example, you might describe what the vandals did, explain how much repairs will cost, or discuss ways to prevent future problems.

A CENTRAL IDEA IS LIMITED

Essays that beginning college or university students write usually contain approximately five to seven paragraphs of about 50 to 100 words. Therefore, you should limit your working topic sentence or thesis, making it as specific as you can. Otherwise, you won't be able to make your point clearly and completely.

LIMIT THE DISCUSSION TO A MANAGEABLE LENGTH

Let's say you want to convince someone to stop smoking. You might limit yourself to three reasons to stop smoking: the health risks, the costs, and its effects on others.

Here's your working thesis:

Break the habit: otherwise, it will ruin your health, empty your wallet, and annoy your friends.

Your working topic sentences, which will control the three body paragraphs, could be as follows:

Smoking causes cancer, emphysema, and heart disease.
You can save hundreds or even thousands of dollars a year by quitting.
Smoking is offensive to friends and family.

LIMITING YOUR CENTRAL IDEA FURTHER

You begin a rough draft by discussing illnesses caused by smoking. However, you soon realize that you can't cover all three reasons for quitting and still keep the essay short. So you limit yourself to the issue of health risks.

Your thesis statement becomes:

Break the habit: smoking causes heart disease, emphysema, and cancer.

Your topic sentences become:

Smoking weakens the heart and impairs circulation.
Smoking is a major cause of emphysema.
Smoking has been linked directly to cancer of the mouth and the esophagus.

DIFFERENCES BETWEEN A TOPIC SENTENCE AND A THESIS

A topic sentence is the sentence that expresses the central idea of a paragraph. A thesis statement is a sentence that expresses the central idea of an essay.

It's a good idea to decide the topic sentence of a paragraph after writing the working version of an essay's thesis. A topic sentence explains one aspect or point in the thesis and, therefore, should always be more specific and limited than a thesis.

REVISE AND REFINE THE CENTRAL IDEA AS YOU WORK

You can revise a central idea whenever you need to. The working version of a topic sentence or thesis statement provides only a starting point and a sense of direction. Don't be afraid to look back to your central ideas and rewrite them often. As a matter of fact, focusing is something you should do throughout the writing process.