5.B Topic Sentences and the Shape of a Body Paragraph (REO-1.M)

A reader decides what a paragraph is about almost immediately because that is how reading works: you hold a claim in mind and sort everything after it as support, complication, or proof. That first guess has to land on something, so writers who want control put the claim where the guess will find it. The topic sentence is a promise. It tells the reader what kind of evidence is coming and what point that evidence is supposed to prove. Once that promise is made, every other sentence in the paragraph is obliged to keep it: develop it, prove it, complicate it, but not wander off into a different claim with different evidence.

Writing one means working backward from your evidence. If the paragraph's real material is an insurance figure, say a report showing insured losses in wildfire zones have tripled since 2015, the topic sentence has to name insurance, not acreage burned or firefighter staffing. A sentence like 'The insurance figures tell a harsher story than the acreage does' sets up exactly that material; anything else in the paragraph is off-topic. Position isn't the rule, function is. A paragraph can open with three sentences of narrative detail, then state its actual claim fourth, with the closing sentences extending that claim. That fourth sentence is still the topic sentence, because the sentences on both sides of it are built to support it, not the other way around.

This sits next to transitions because the two jobs get confused. A sentence that announces a shift in attention, 'It is worth pausing here on the counties the report set aside,' is a transition, not a claim. It tells the reader a turn is coming but hasn't made any point yet. Recognizing that difference is what lets a reader, or a writer, find the actual topic sentence instead of mistaking the doorway for the room.