alpha reliability coefficient

n. In psychometrics, an index of internal consistency among items in a scale. Mathematically, the average of all possible split-half reliability coefficients corrected for attenuation of a scale with more than two possible outcomes and commonly used with Likert type scales. It ranges from 0, no internal consistency, to 1, which indicates complete internal consistency, or no difference among the items in the way in which they are answered by test takers. Also called Cronbach’s alpha and the alpha coefficient.