Analysis cronbachs alpha reliability in spss spss expert. Cronbach alpha free statistics and forecasting software. Descargar spss gratis ultima version en espanol en ccm ccm. Items 1 and 2 are responded using a 6point likert scale. Which would be the more appropriate statistic to measure internal consistency, the raw or standardized. Cronbach s alpha is the most common measure of internal consistency reliability. It is most commonly used when you have multiple likert questions in a surveyquestionnaire that form a scale and you wish to determine if the scale is reliable. In spss, how do i compute cronbachs alpha statistic to test. Cronbach s alpha coefficient increases either as the number of items variables increases, or as the average interitem correlations increase i. Cronbachs alpha is most commonly used when you want to assess the internal consistency of a questionnaire or survey that is made up of multiple likerttype scales and items. I am currently evaluating the validity and reliability of a scale. Cronbachs alpha is the most common measure of internal consistency reliability. My ultimate goal is to create a scale with the three variables using something like. To run the same test in stata or sas, see archived.
This article focuses on the introduction of theory and practice analyzing cronbachs alpha reliability. In r, there are several packages that calculate cronbach s alpha. In stata, how do i compute cronbach s alpha statistic to test reliability. Even yet, many metrics exist to provide evidence of internal consistency reliability, but cronbachs alpha is perhaps the most popular of these. Abstract the analysis and report of a psychological measures internal consistency is a well established requirement in the scientific community. Validez y confiabilidad con spss validez estadisticas. With missing data, listwise deletion is a possible way to go the only option in spss or packages mbess and psy btw.
This free online software calculator computes the cronbach alpha statistics for a set of items that are believed to represent a latent variable construct. Cronbach s alpha measures the internal consistency of scales that are made up of multiple items. Among the several available methods to estimate internal consistency, cronbachs. Cronbachs alpha in this tutorial you will learn how to produce a simple and commonly used measure of reliability. Cronbachs coefficient alpha provides an indication of the average correlation among all of the items that make up the scale. I noticed that cronbach s alpha based on standardized items in spss is substantially higher than the raw alpha. Cronbach s alpha is not related to the concepts of independent and dependent variables.
Cronbachs alpha in spss statistics procedure, output. Cronbachs alpha in spss statistics procedure, output and. As the average interitem correlation increases, cronbachs alpha increases as well holding the number of items constant. Lets work through an example of how to compute cronbachs alpha using spss, and how to check the dimensionality of the scale using factor analysis.