Definition Causality
We speak of causality if there is an interdependence of cause and effect between two variables. Correlation refers to variables that are thought to be related to one another. A person who is a heavy smoker (variable X) has a higher risk of suffering from lung cancer (variable Y). It is important to bear in mind that a correlation in itself does not prove causality. Two variables can have a statistical relationship without there actually being a mutual influence. In this context we also speak of spurious correlation.
Please note that the definitions in our statistics encyclopedia are simplified explanations of terms. Our goal is to make the definitions accessible for a broad audience; thus it is possible that some definitions do not adhere entirely to scientific standards.