Coefficient alpha is almost universally applied to assess reliability of scales in psychology. We argue that researchers should consider alternatives to coefficient alpha. Our preference is for structural equation modeling (SEM) estimates of reliability because they are informative and allow for an empirical evaluation of the assumptions underlying them. An example is presented to illustrate the advantages of SEM estimates of reliability.
Barchard, K.A., & Hakstian, A.R. (1997). The effects of sampling model on inference with coefficient alpha. Educational and Psychological Measurement, 57, 893-905.
2.
Becker, G. ( 2000). How important is transient error in estimating reliability? Going beyond simulation studies. Psychological Methods, 5, 370-379.
Callendar, J.C., & Osburn, H.G. ( 1977a). A method for maximizing split-half reliability coefficients . Educational and Psychological Measurement, 37, 819-825.
5.
Callendar, J.C., & Osburn, H.G. ( 1977b). A computer program for maximizing and cross-validating split-half reliability coefficients. Educational and Psychological Measurement, 37, 787-789.
6.
Callendar, J.C., & Osburn, H.G. ( 1979). An empirical comparison of coefficient alpha, Guttman’s lambda2, and msplit maximized split-half reliability estimates. Journal of Educational Measurement, 16, 89-99.
7.
Cortina, J.M. ( 1993). What is coefficient alpha? An examination of theory and applications. Journal of Applied Psychology, 78, 98-104.
8.
Cronbach, L.J. ( 1951). Coefficient alpha and the internal structure of tests . Psychometrika, 16, 297-334.
9.
Cronbach, L.J. ( 2004). My current thoughts on coefficient alpha and successor procedures. Educational and Psychological Measurement, 64, 391-418.
10.
Cronbach, L.J., & Gleser, G.C. ( 1965). Psychological tests and personnel decisions. Urbana: University of Illinois Press.
11.
Embretson, S.E., & Reise, S. ( 2000). Item response theory for psychologists. Mahwah, NJ: Erlbaum.
12.
Feldt, L.S., & Qualls, A.L. ( 1996). Bias in coefficient alpha arising from heterogeneity of test content. Applied Measurement in Education, 9, 277-286.
13.
Finney, S., & DiStefano, C. ( 2006). Non-normal and categorical data in structural equation modeling. In G. R. Hancock & R. O. Mueller (Eds.), Structural equation modeling: A second course (pp. 269-314). Greenwich, CT: Information Age.
14.
Fleishman, J., & Benson, J. ( 1987). Using LISREL to evaluate measurement models and scale reliability. Educational and Psychological Measurement, 47, 925-939.
15.
Flora, D.B., & Curran, P.J. ( 2004). An empirical evaluation of alternative methods of estimation for confirmatory factor analysis with ordinal data. Psychological Methods, 9, 466-491.
16.
George, D., & Mallery, P. ( 2003). SPSS for Windows step by step: A simple guide and reference, 11.0 update (4th ed.). Boston, MA: Allyn & Bacon.
17.
Green, S.B. ( 1983). Identifiability of spurious factors using linear factor analysis with binary items. Applied Psychological Measurement , 7(2), 139-147.
18.
Green, S.B. ( 2003). A coefficient alpha for test-retest data. Psychological Methods, 8, 88-101.
19.
Green, S.B., Akey, T.M., Fleming, K.K., Hershberger, S.L., & Marquis, J.G. ( 1997). Effect of the number of scale points on chi-square fit indices in confirmatory factor analysis. Structural Equation Modeling, 4, 108-120.
20.
Green, S.B., & Hershberger, S.L. (2000). Correlated errors in true score models and their effect on coefficient alpha. Structural Equation Modeling, 7, 251-270.
21.
Green, S.B., Lissitz, R.W., & Mulaik, S. ( 1977). Limitations of coefficient alpha as an index of text unidimensionality. Educational and Psychological Measurement , 37, 827-839.
22.
Green, S.B., & Thompson, M.S. (2003). Structural equation modeling in clinical research. In M. C. Roberts & S. S. Illardi (Eds.), Methods of research in clinical psychology: A handbook. (pp. 138-175). London, UK: Blackwell.
23.
Green, S.B., & Yang, Y. ( 2005). K-split coefficient alpha. Paper presented at the Annual Meeting of American Education Research Association , Montreal, Québec, Canada.
24.
Green, S.B., & Yang, Y. ( 2009a). Commentary on coefficient alpha: A cautionary tale. Psychometrika, 74(1), 121-135.
25.
Green, S.B., & Yang, Y. ( 2009b). Reliability of summed item scores using structural equation modeling: An alternative to coefficient alpha. Psychometrika , 74, 155-167.
26.
Guttman, L.A. ( 1945). A basis for analyzing test-retest reliability. Psychometrika, 10, 255-282.
27.
Hogan, T.P., Benjamin, A., & Brezinski, K.L. (2000). Reliability methods: A note on the frequency of use of various types. Educational and Psychological Measurement, 60, 523-531.
28.
Hunter, J.E., & Schmidt, F.L. ( 1996). Measurement error in psychological research: Lessons from 26 research scenarios. Psychological Methods, 1, 199-223.
Komaroff, E. ( 1997). Effect of simultaneous violations of essential τ-equivalence and uncorrelated error on coefficient α. Applied Psychological Measurement, 21, 337-348.
31.
Lei, P.-W. ( 2009). Evaluating estimation methods for ordinal data in structural equation modeling. Quality & Quantity, 43, 495-507.
32.
Lord, F.M. ( 1955). Sampling fluctuations resulting from the sampling of test items. Psychometrika, 20, 1-22.
33.
Maxwell, A.E. ( 1968). The effect of correlated errors on estimates of reliability coefficients. Educational and Psychological Measurement, 28, 803-811.
34.
McDonald, R.P. ( 1978). Generalizability in factorable domains: "Domain validity and generalizability": 1. Educational and Psychological Measurement , 38, 75-79.
35.
McDonald, R.P. ( 1999). Test theory: A unified treatment. Hillsdale, NJ: Erlbaum.
36.
Miller, M.B. ( 1995). Coefficient alpha: A basic introduction from the perspectives of classical test theory and structural equation modeling. Structural Equation Modeling, 2, 255-273.
37.
Muthén, B., & Kaplan, D. ( 1992). A comparison of some methodologies for the factor-analysis of non-normal Likert variables: A note on the size of the model. British Journal of Mathematical and Statistical Psychology, 45, 19-30.
Novick, M.R., & Lewis, C. ( 1967). Coefficient alpha and the reliability of composite measurements . Psychometrika, 32, 1-13.
40.
Nunnally, J.C. ( 1978). Psychometric theory (2nd ed.). New York, NY: McGraw-Hill.
41.
Osburn, H.G. ( 2000). Coefficient alpha and related internal consistency reliability coefficients. Psychological Methods, 5, 343-355.
42.
Peterson, R.A. ( 1994). A meta-analysis of Cronbach’s coefficient alpha . Journal of Consumer Research, 21, 381-391.
43.
Raju, N.S. ( 1970). New formula for estimating total test reliability from parts of unequal lengths. Proceedings of the Annual Convention of the American Psychological Association, 5, 143-144.
44.
Raykov, T. ( 1997a). Estimation of composite reliability for congeneric measures . Applied Psychological Measurement, 21, 173-184.
45.
Raykov, T. ( 1997b). Scale reliability, Cronbach’s coefficient alpha, and violations of essential tau equivalence with fixed congeneric components . Multivariate Behavioral Research, 32, 329-353.
46.
Raykov, T. ( 1998). Coefficient alpha and composite reliability with interrelated nonhomogeneous items. Applied Psychological Measurement, 22, 375-385.
47.
Raykov, T., & Shrout, P.E. ( 2002). Reliability of scales with general structure: Point and interval estimation using a structural equation modeling approach. Structural Equation Modeling, 9, 195-212.
48.
Reise, S.P., Morizot, J., & Hays, R.D. ( 2007). The role of the bifactor model in resolving dimensionality issues in health outcomes measures. Quality of Life Research , 16, 19-31.
Revelle, W., & Zinbarg, R.E. ( 2009). Coefficient alpha, beta, omega, and the GLB: Comments on Sijtsma. Psychometrika, 74, 145-154.
51.
Rozeboom, W.W. ( 1966). Foundations of the theory of prediction. Homewood, IL: Dorsey.
52.
Schmitt, N. ( 1996). Uses and abuses of coefficient alpha. Psychological Assessment, 8, 350-353.
53.
Sijtsma, K. ( 2009). On the use, the misuse, and the very limited usefulness of Cronbach’s alpha. Psychometrika, 74(1), 107-120.
54.
Steinberg, L. ( 2001). The consequences of pairing questions: Context effects in personality measurement. Journal of Personality and Social Psychology, 81, 332-342.
55.
Steinberg, L., & Thissen, D. ( 1996). Uses of item response theory and the testlet concept in the measurement of psychopathology. Psychological Methods , 1, 81-97.
56.
Thompson, B.L., Green, S.B., & Yang, Y. ( 2010). Assessment of the maximal split-half coefficient to estimate reliability. Educational and Psychological Measurement, 70, 232-251.
57.
Wainer, H., & Kiely, G. ( 1987). Item clusters and computerized adaptive testing: The case for testlets. Journal of Educational Measurement, 24, 189-205.
58.
Yang, Y., & Green, S.B. ( 2010a). A note on structural equation modeling estimates of reliability. Structural Equation Modeling, 17, 66-81.
59.
Yang, Y., & Green, S.B. ( 2010b, May). Evaluation of nonlinear SEM reliability coefficients . Paper presented at Annual Meeting of the American Educational Research Association, Denver, CO.
60.
Yen, W.M. ( 1993). Scaling performance assessments: Strategies for managing local item dependence. Journal of Educational Measurement , 30, 187-214.
61.
Zimmerman, D.W., Zumbo, R.D., & Lalonde, C. ( 1993). Coefficient alpha as an estimate of test reliability under violation of two assumptions. Educational and Psychological Measurement, 53, 33-49.
