What does the phrase "causation requires correlation" indicate?

The phrase "causation requires correlation" indicates that for one event or variable to be considered a cause of another, there must be some form of relationship or connection between them, which is defined as correlation. In the context of scientific studies and data analysis, this means that if we want to establish that a particular factor causes an effect, we need to observe a correlation between them.

This correlation can be seen through various means, such as statistical data showing that as one variable changes, so does the other. However, establishing correlation is merely the first step in asserting causation. It suggests a possible link but does not confirm that one directly causes the other, as other factors may influence both.

Understanding this concept is fundamental in fields like biomedical engineering, where researchers need to investigate relationships between various biological factors and outcomes. In this context, recognizing that correlation is a prerequisite for establishing causation helps guide the direction of research and the interpretation of results.