Test Homogeneity, Reliability, and Generalizability
Roderick P. McDonald · Psychology Press eBooks · 2013
If two variables are correlated, there are at least three ways we can "explain" the presence of a relationship between them. 1. It may be that one variable (partly) determines the other, in a sense that has no converse. We say that one is a cause of the other. For example, observing a rat in an activity cage, we say that hunger causes activity. And after a good workout we say activity causes hunger. But we do not say that activity and hunger are merely contingendy associated. Both the meaning and the verification of causal claims are deep and controversial matters. It is to be hoped that the reader, like the writer, makes a distinction between "teaching causes learning" and "teaching and learning are activities often found together."