Calculating, interpreting, and reporting cronbachs alpha. Most items appeared to be worthy of retention, resulting in a decrease in the alpha if deleted. Cronbachs alpha is a measure used to assess the reliability, or internal consistency, of a set of scale or test items. Useofasubjectivehealthmeasureonchineselowbackpainpatientsinhongkongarrans. This result shows that the data collected in the study were reliable salvucci et al. Cronbach s alpha is the average value of the reliability coefficients one would obtained for all possible combinations of items when split into two halftests. If, in addition to measuring internal consistency, you wish to provide evidence that the scale. Interval estimation, hypothesis testing, and sample size planning article pdf available in journal of organizational behavior 361 october 2014 with 23,847 reads. Researcherdeveloped multipleitem instruments with likerttype scaling number % reliability coefficients reported analysis strategy.
Cronbach s 1951 alpha was developed based on the necessity to evaluate items scored in multiple answer categories. Cronbach s alpha is a measure of internal consistency, that is, how closely related a set of items are as a group. Using and interpreting cronbachs alpha university of. Cronbachs alpha is reported using the small greek letter alpha. Cronbach s alpha showed the questionnaire to reach acceptable reliability. One property of alpha cronbach, 1951 is it is one type of internal consistency coefficient. In other words, the reliability of any given measurement refers to the extent to which it is a consistent measure of a concept, and cronbachs alpha is one way of measuring the strength of that consistency.
Development of a questionnaire to assess the dietary behaviors of. In the study, the cronbach alpha coefficient for the reliability of the research data was calculated as 0. A high value for alpha does not imply that the measure is unidimensional. It is considered to be a measure of scale reliability. Before alpha, researchers were limited to estimating internal consistency of only dichotomously scored items using the kr20 formula. A reliability analysis was carried out on the perceived task values scale comprising 8 items.
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