Reliability

According to the Standards for Educational and Psychological Testing, reliability (also referred to as measurement precision) refers to the consistency of assessment results over independent administrations of the testing procedure. The assessment results can be examinees’ scores or raters’ ratings of examinees’ performances on an assessment. Reliability is a central concept in measurement and a necessary condition when building a validity argument. Indeed, if an assessment fails to yield consistent results, it is imprudent to make any inferences about what a score signifies. Reliability is high if the scores or ratings for each examinee are consistent over replications of the testing procedure. Reliability coefficients range from 0 to 1, with 0 being extremely unreliable and 1 representing perfect reliability. There is no absolute critical value ...