The indeterminacy of components and the definition of common factors

Results given by Sohönemann & Steiger (1976) are related to theory given by McDonald (1975) and McDonald & Burr (1967). From the relation between split‐half estimators of a common factor, it is shown that the factor is uniquely defined in a behaviour domain by a set of marker variables, if it is defined by them at all. Regression components obtained from split‐halves do not, in general, have higher correlations than factor score estimators, hence there is no reason to prefer regression components to common factors on grounds of determinacy.