bias

Bias is a leaning a passage does not admit: what it counts, what it leaves out, and which voice it never reports. The word covers two faults here: a writer's leaning, and a skewed sample. A writer's bias is the same fault as an unstated assumption seen from the other side: a claim leans on a premise, and the premise is where the leaning shows. A sampling bias is narrower — a survey mailed to drivers reports what drivers think, and the conclusion drawn from that is large. The method has two steps. First name the premise the claim needs: an early-morning drive shows how the benches are used, or the people who answered speak for the whole downtown. Then say what would break it — the finding that would have to be true, or the group that was never asked. Items ask for the assumption a claim rests on, the frame a report puts around its own finding, and the evidence that would weaken the claim most. The premise is usually not printed in the passage, because it is what the passage takes for granted; when it is printed, the question asks how the conclusion depends on that sentence, and an option that only restates the passage's own figures is the evidence rather than the belief under it.