One problem with using archival data (e. g., existing records of disturbances) to demonstrate that exposure to uncomfortable levels of heat causes people to behave aggressively is that

You are the on-duty desk sergeant at the local police station. a man walks in and says, "i killed someone and want to confess." you grab your digital voice recorder and direct the man to a chair. he sits down and tells the tale of what turns out to be a first-degree murder. you record every word, including the numerous instances in which you said, "uh- huh" and "i see." satisfied that the subject did, indeed, commit a murder, you place him under arrest. the confession is: