Results on the Standard Error of the Coefficient Alpha Index of Reliability

Marketing Science, Vol. 24, No. 2, Spring 2005, pp. 294-301

8 Pages Posted: 21 Nov 2015 Last revised: 19 Feb 2016

Date Written: 2005

Abstract

In this research, we investigate the behavior of Cronbach’s coefficient alpha and its new standard error. We systematically analyze the effects of sample size, scale length, strength of item intercorrelations, and scale dimensionality. We demonstrate the beneficial effects of sample size on alpha’s standard error and of scale length and the strengths of item intercorrelations (effects that are substitutes in their benefits) on both alpha and its standard error. Our findings also speak to this adage: Heterogeneity within the item covariance matrix (e.g., through multidimensionality or poor items) negatively impacts reliability by decreasing the precision of the estimation. We also examined the question of “equilibrium” scale length, showing the conditions for which it is optimal to add no items, or one, or multiple items to a scale. In terms of “best practices,” we recommend that researchers report a confidence interval or standard error along with the coefficient alpha point estimate.

Suggested Citation

Duhachek, Adam and Coughlan, Anne T. and Iacobucci, Dawn, Results on the Standard Error of the Coefficient Alpha Index of Reliability (2005). Marketing Science, Vol. 24, No. 2, Spring 2005, pp. 294-301, Available at SSRN: https://ssrn.com/abstract=2693300

Adam Duhachek

Indiana University Bloomington ( email )

Dept of Biology
100 South Indiana Ave.
Bloomington, IN 47405
United States

Anne T. Coughlan

Kellogg School, Northwestern University ( email )

2211 Campus Drive
Evanston, IL 60208
United States
847-491-3522 (Phone)

HOME PAGE: http://www.kellogg.nwu.edu/faculty/bio/Coughlan.htm

Dawn Iacobucci (Contact Author)

Vanderbilt University - Marketing ( email )

Nashville, TN 37203
United States

Do you have a job opening that you would like to promote on SSRN?

Paper statistics

Downloads
17
Abstract Views
351
PlumX Metrics