拜登曲线当然是 circumstantial evidence。
Circumstantial evidence is indirect evidence that requires an inference to connect it to a conclusion of fact. It does not directly prove a fact but suggests it, such as a fingerprint at a crime scene suggesting a person's presence or seeing someone flee the scene. Unlike direct evidence, like an eyewitness account, circumstantial evidence relies on reasoning and a collection of facts to establish the truth. Examples include physical evidence (fingerprints, DNA), scientific evidence, human behavior, or indirect witness testimony.
