Cronbach’s alpha is widely used in social science research to estimate the internal consistency reliability of a measurement scale. However, when items are not strictly parallel, the Cronbach’s alpha coefficient provides a lower bound estimate of true reliability. This estimate may be further biased downward when items are dichotomous. The estimation of standardized Cronbach’s alpha for a scale...

The reliability of a composite score is a fundamental and important topic in psychology and related disciplines. The most commonly used reliability estimate of a composite score is coefficient alpha. However, under regularity conditions, the population value of coefficient alpha is only a lower bound on the population reliability, unless the items are essentially tau-equivalent, an assumption t...

objectives: one of the problems in the process of assessment and evaluation, especially of clinical training in rehabilitation disciplines, is the lack of an instrument with objective criteria for evaluation. considering the effects of appropriate evaluation on quality assurance of clinical training, the aim of the present study was to design a valid and reliable tool for general evaluation of ...

background: alcohol consumption is one of the main health problems in most countries. the purpose of the present study is to evaluate the reliability and validity of alcohol use disorders identification test (audit). methods: by employing the method of available sampling, 70 alcoholic patients were included as case group and 70 normal age, gender and education matched individuals were also incl...

be viewed within a much larger system of reliability analysis, generalizability theory. Moreover, alpha focused attention on reliability coefficients when that attention should instead be cast on measurement error and the standard error of measurement. For Cronbach, the extension of alpha (and classical test theory) came when Fisherian notions of experimental design and analysis of variance wer...