As compelling as the above example may be, an obvious question concerns how one determines homogeneity in the first place. In our view, the statement that a construct is homogeneous is a statement of theory that, itself, needs to be investigated empirically. Just as theory validation is an indeterminate and ongoing process, so is determination of homogeneity. Suppose that one's theory holds that the construct is a single dimension, factor analyses have supported the single dimension hypothesis, and there is no evidence that different components of the construct play different roles in understanding psychological processes (e.g., different components are not understood to have different correlates with other constructs). When that is the case, researchers can and should appropriately treat their measure of the construct as unidimensional and test theories on that basis.
