Abstract

LEDESMA, Rubén. AlphaCI: a computer program for computing confidence intervals around Cronbach's alfa coefficient. PsicoUSF [online]. 2004, vol.9, n.1, pp.31-37. ISSN 1413-8271.

Cronbach's alpha coefficient is the most popular way of estimating reliability in measurement scales based on Classic Test Theory. When estimating it, researchers usually omit to report confidence intervals of this coefficient, as it is not only recommended by experts, but also required by some journal's guidelines. This situation is because the different methods of estimating confidence intervals are not well-known by researchers, as well as they are not being available among the most popular statistical packages. Therefore, this paper describes a computer program integrated into the ViSta statistical system, which allows computing confidence intervals based on the classical approach and using bootstrap technique. It is hoped that this work promotes the inclusion of confidence intervals of reliability measures, by increasing the availability of the required computer tools. The program is free and it can be obtained by sending an e-mail to the author.

Keywords : Cronbach's alpha; Confidence intervals; Computer program.

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