Characteristics of a Good Topic Sentence

1. A good topic sentence provides an accurate indication of what will follow in the rest of the paragraph.

Weak example. People rarely give firefighters the credit they deserve for such a physically and emotionally demanding job. (The paragraph is about a specific incident that involved firefighters; therefore, this topic sentence is too general.)
Stronger example. During the October riots, Unit 3B went beyond the call of duty. (This topic sentence is more specific and indicates that the paragraph will contain information about a particular incident involving Unit 3B.)

2. A good topic sentence contains both a topic and a controlling idea or opinion.

Weak example. In this paper, I am going to discuss the rising suicide rate among young professionals. (This topic sentence provides a main idea, but it does not present a controlling idea, or thesis.)
Stronger example. The rising suicide rate among young professionals is a cause for immediate concern. (This topic sentence presents the writer’s opinion on the subject of rising suicide rates among young professionals.)

3. A good topic sentence is clear and easy to follow.

Weak example. In general, writing an essay, thesis, or other academic or nonacademic document is considerably easier and of much higher quality if you first construct an outline, of which there are many different types. (This topic sentence includes a main idea and a controlling thesis, but both are buried beneath the confusing sentence structure and unnecessary vocabulary. These obstacles make it difficult for the reader to follow.)
Stronger example. Most forms of writing can be improved by first creating an outline. (This topic sentence cuts out unnecessary verbiage and simplifies the previous statement, making it easier for the reader to follow.)

4. A good topic sentence does not include supporting details.

Weak example. Salaries should be capped in baseball for many reasons, most importantly so we don’t allow the same team to win year after year. (This topic sentence includes a supporting detail that should be included later in the paragraph to back up the main point.)
Stronger example. Introducing a salary cap would improve the game of baseball for many reasons. (This topic sentence omits the additional supporting detail so that it can be expanded upon later in the paragraph.)

5. A good topic sentence engages the reader by using interesting vocabulary.

Weak example. The military deserves better equipment. (This topic sentence includes a main idea and a controlling thesis, but the language is bland and unexciting.)
Stronger example.The appalling lack of resources provided to the military is outrageous and requires our immediate attention. (This topic sentence reiterates the same idea and controlling thesis, but adjectives such as appalling and immediate better engage the reader. These words also indicate the writer’s tone.)