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Developing an Effective Topic Sentence

Developing an Effective Topic Sentence

Author: Sophia Tutorial

Identify the elements of an effective topic sentence.

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This tutorial will cover topic sentences—what they are, how they fit in a paragraph, and how they can be written and revised to be as effective as possible. Discussion will include:
  1. Topic Sentences in Paragraphs
  2. Scope of a Topic Sentence
  3. Revising Topic Sentences

1. Topic Sentences in Paragraphs

If you’re going to talk about topic sentences, you need to start by talking about paragraphs. You’ll recall that a paragraph is one unit or chunk of writing that’s meant to cover one main idea in full.

Usually, a paragraph is part of a larger piece of writing, and it is distinguished from other paragraphs by having either the first line indented or by having a blank line separating it from the paragraphs above or below.

Since a paragraph is meant to cover just one central idea, paragraphs are usually between three and seven sentences, which might be roughly 100 to 200 words or so.

However, a paragraph isn’t just any sentences thrown together. There’s a structure, which usually looks something like this:

  1. Topic sentence
  2. Supporting sentences
  3. Concluding sentence

In addition to simply beginning a paragraph, a topic sentence captures the main point or controlling idea of a paragraph.

A controlling idea is just the main idea around which the whole paragraph revolves; it’s the purpose of the paragraph. Every other sentence is designed to support and develop that main, controlling idea.

Read the following paragraph and consider the topic sentence.


Here it’s clear that “Traveling to other countries is one way that people can become more tolerant” is the topic sentence. See how it announces what the paragraph is going to be about? It’s almost like a title telling you what to expect from this paragraph.

For this reason, topic sentences are usually, though not always, the first sentence in a paragraph. That way, readers are introduced to the paragraph through this topic sentence.

Topic Sentence
A sentence that captures the main point or controlling idea of a paragraph

2. Scope of a Topic Sentence

Now that you know what a topic sentence is, it’s time to learn how to write a strong and effective one.

There are a few guidelines to keep in mind when writing a topic sentence:

  • Introduce the main idea
  • Avoid being too narrow
  • Avoid being too broad
  • Focus on the topic

If your topic sentence is too narrow, your readers will only know to expect one aspect of the paragraph. If it’s too broad, your readers won’t know what to expect from the paragraph.

Try to focus on the topic and what the supporting sentences will do. Then, summarize that as the topic sentence.

Here is an example paragraph with a topic sentence that’s too narrow.


See how the topic sentence doesn’t actually introduce the material that the paragraph covers? It’s not effectively providing a summary of what this whole paragraph is about, just of one of the points.

Now here’s a topic sentence that’s too broad.


Notice how big this idea is. Do you think all of the material this introduces could be sufficiently covered in a mere three to seven sentences? No way. And do you know specifically that this paragraph is going to be about dress codes? No.

A topic sentence that’s too broad will usually require several paragraphs to explain all of its material, and thus should be narrowed down to address just the main point of the single paragraph.

Here are three options for a new topic sentence for the paragraph we just discussed. Which do you think is the best or most effective topic sentence?

The third one is too broad. “More productive” in what way? The sentence doesn’t tell you. The second one is too narrow. Community is just one of the points in the paragraph.

The first one, however, introduces the paragraph effectively by announcing the main point and fully addressing both elements of the content of this paragraph.

Now it’s your turn. Here is a paragraph that’s missing its topic sentence. Read through, then decide what you think the main idea of this paragraph is.

Looking at the last sentence can give you a clue, as that concluding sentence is there to sum up the main idea of the paragraph. With that in mind, the completed paragraph with the topic sentence might look like this:


3. Revising Topic Sentences

Sometimes, after you’ve written a topic sentence and then a full paragraph, you might realize that what you wrote in the paragraph has transformed in the process of writing and no longer matches that topic sentence.

Perhaps you realize that you had a more narrow focus as you wrote, or perhaps you changed your opinion in the process of writing. That isn’t a bad thing.

In fact, it’s great because writing is a process, not a product, and it should include rethinking, revising, and rewriting. However, it does mean that you will need to revise your topic sentence so that it remains aligned with the content of your paragraph.

The following is a revised version of the paragraph about dinner parties.


Obviously the content of the paragraph is a little different than the original topic sentence (“When you’re throwing a dinner party, it’s important that you pay attention to everyone’s physical comfort”) suggests.

How should you revise this topic sentence? Consider the following options, and decide which you like best.

Options 1 and 3 are a little too broad. Conversely, options 2 and 4 are too specific; they’re not covering everything. Number 5, however, explains that this paragraph will specifically cover the issue of sharing the menu with dinner guests in order to make sure that they feel comfortable at your party. So number 5 would be the best choice.

In this tutorial, you learned about topic sentences in paragraphs, and how they are essential to communicating a paragraph’s controlling idea.

You then learned strategies for writing effective topic sentences, particularly how to control the scope of a topic sentence by focusing on the main idea and avoiding statements that are either too broad or too narrow.

Finally, you practiced revising topic sentences to prepare for instances when the content of the paragraph shifts during the writing process.

Good luck!

Source: This work is adapted from Sophia author Martina Shabram.

Terms to Know
Topic Sentence

A sentence that captures the main point or controlling idea of a paragraph.