Confusion in the literature between the concepts of internal consistency and homogeneity has led to a misuse of coefficient alpha as an index of item homogeneity. Coefficient alpha is actually a complexly determined test statistic, item homogeneity only being one influence on its magnitude. The related statistic, the average intercorrelation, has similar difficulties. Several indices of item homogeneity derived from the model of common factor analysis are offered as alternatives.
Get full access to this article
View all access options for this article.
References
1.
Allen, M. P.Construction of composite measures by the canonical factor-regression method. In H. L. Costner (Ed.), Sociological methodology 1973-1974 . San Francisco: Jossey-Bass , 1974.
2.
Armor, D. J.Theta reliability and factor scaling. In H. L. Costner (Ed.), Sociological methodology 1973-1974. San Francisco : Jossey-Bass, 1974.
3.
Crano, W. D. and Marilynn B. Brewer.Principles of research in social psychology . New York: McGraw-Hill, 1973.
4.
Cronbach, L. J.Coefficient alpha and the internal structure of tests. Psychometrika, 1951, 16, 297-334.
5.
Cronbach, L. J.Essentials of psychological testing (2nd ed.). New York : Harper and Row, 1960.
6.
Edwards, A. L.Techniques of attitude scale construction. New York: Appleton, Century, Crofts, 1957.
7.
Gulliksen, H.Theory of mental tests. New York: Wiley, 1950 .
8.
Lord, F. M. and M. R. Novick.Statistical theories of mental test scores. Reading, Massachusetts: Addison-Wesley , 1968.
9.
Nunnally, J. C.Introduction to psychological measurement. New York: McGraw-Hill , 1970.
10.
Standards for educational and psychological tests and manuals. Washington, D. C.: American Psychological Association, 1966.
11.
Upshaw, H. S.Attitude measurement. In H. M. Blalock, Jr. and A. B. Blalock (Eds.), Methodology in social research. New York: McGraw-Hill , 1968.
