Which fallacy occurs when one attributes a cause-and-effect relationship where none exists, as in the case of a decrease in presidential popularity being linked to a new chief of staff?

The fallacy known as Post Hoc occurs when an incorrect assumption is made about the relationship between two events, suggesting that because one event follows another, the first event must be the cause of the second. In the example given, linking a decrease in presidential popularity directly to the appointment of a new chief of staff is a classic illustration of this fallacy. It implies causation without sufficient evidence to support that the change in staff is responsible for the shift in public perception.

This fallacy is particularly common in situations where there are multiple factors influencing outcomes, yet an oversimplified cause-and-effect relationship is suggested. By relying solely on the sequence of events (the new chief of staff being hired followed by a change in popularity), one ignores other possible reasons for the decrease, such as external political factors, economic conditions, or specific actions taken by the president that could also contribute to shifts in popularity. This misattribution of causality leads to faulty reasoning and conclusions.