Cronbachs alpha can be written as a function of the number of test items and the average intercorrelation among the items. Most items appeared to be worthy of retention, resulting in a decrease in the alpha if deleted. This free online software calculator computes the cronbach alpha statistics for a set of items that are believed to represent a latent variable construct. The tool has internal consistency as assessed with the use of the cronbach coefficient alpha. Cronbachs alpha showed the questionnaire to reach acceptable reliability. Pdf cronbachs alpha is one of the most widely used measures of reliability in the social and organizational sciences. Total scale summated score analysis exclusively andor subscales calculating cronbachs alpha coefficient for internal consistency a single statement item was presented to each student and then this same statement was presented to the student 3 weeks later. As such, removal of this item should be considered.
The one exception to this was item 4, which would increase the alpha to. Cronbachs alpha in spss statistics procedure, output. A testretest reliability coefficient was calculated on this. Cronbach alpha free statistics and forecasting software. Technically speaking, cronbachs alpha is not a statistical test it is a coefficient of reliability or consistency. This coefficient is a measure of the squared correlation between observed scores and true scores, reliability being thus measured in terms of the ratio of the true. Cronbachs alpha is the most common measure of internal consistency reliability. Below, for conceptual purposes, we show the formula for the cronbachs alpha. Calculating, interpreting, and reporting cronbachs alpha.