In academic writing, readers expect each paragraph to have a sentence or two that captures its main point. They’re often called “topic sentences,” though many prefer to call them “key sentences.” There are at least two downsides of the phrase “topic sentence.” First, it makes it seem like the paramount job of that sentence is simply to announce the topic of the paragraph. Second, it makes it seem like the topic sentence must always be a single grammatical sentence. Calling it a “key sentence” reminds us that it expresses the central idea of the paragraph. And sometimes a question or a two-sentence construction functions as the key.
Key sentences in academic writing do two things. First, they establish the main point that the rest of the paragraph supports. Second, they situate each paragraph within the sequence of the argument, a task that requires transitioning from the prior paragraph.
A last thing to note about key sentences is that academic readers expect them to be at the beginning of the paragraph. This placement helps readers comprehend your argument. However, keep in mind that this isn’t a rule. Sometimes the paragraph’s purpose in a larger piece of writing necessitates that its topic sentence occur elsewhere.
Attribution:
English Composition I. Schoolcraft College.
