Image by Lorenzo Cafaro from Pixabay LEARNING Cronbach’s Alpha A correlation-based statistic that measures a scale’s internal reliability Lorenz Duremdes, Autobiography Dec 1 · 1 min read Cronbach’s alpha Cronbach's alpha In statistics ( classical test theory), Cronbach's (alpha) [1] is a name used for tau-equivalent reliability ()[2] as... en.wikipedia.org Cronbach’s alpha is an indicator of correlation between questions / items i.e. alpha reliability. It is used to measure the internal reliability of those questions, namely whether they measure what they intend to measure. In psychology, when questions measure what they intend to measure, we call them psychometrically validated questions. When we have a set of questions with high variance that produce low score variance , Cronbach’s alpha is low. This is because each individual question doesn’t tend to measure what they intend to measure, again, because of their high variance. When question variance is high together with high score variance, Cronbach’s alpha is high. This, then, means that each individual question tends to measure what has to be measured. A high Cronbach’s alpha seems to be synonymous with “high alpha reliability”. Internal validity Internal validity means “The extent to which we can draw cause-and-effect inferences from a study”. Some rights reserved Research Statistics Mathematics Science Surveys Discover Medium Welcome to a place where words matter. On Medium, smart voices and original ideas take center stage - with no ads in sight. Watch Make Medium yours Follow all the topics you care about, and we’ll deliver the best stories for you to your homepage and inbox. Explore Become a member Get unlimited access to the best stories on Medium — and support writers while you’re at it. Just $5/month. Upgrade About Help Legal