It is the typical distance of those scores (all for the same test taker) from their average. The CSEM indicates how much those scores would vary. Since different editions of this exam contain different questions, a test taker’s score would not be exactly the same on all possible editions of the exam. For CLEP tests, the CSEM is reported for the score level that corresponds to the recommended C-level credit-granting score. That is, the reliability estimate is conditional on the score level there are then different estimates for different score levels and these are referred to as Conditional Standard Errors of Measurement, or CSEMs. Tests can be more reliable at some score levels than at other levels. If the reliability coefficient of the test were 1.00 (if it perfectly measured the candidate's knowledge), the SEM would be zero.Īn additional index of reliability is the conditional standard of error of measurement (CSEM). The SEM is inversely related to the reliability coefficient. Similarly, intervals extending two standard errors above and below the true score will include 95% of the test taker’s obtained scores. Intervals extending one standard error above and below the true score for a test taker will include 68% of that test taker’s obtained scores. It is expressed in score units of the test. This hypothetical average over all editions of the test is referred to as the true score. The SEM is an estimate of the amount by which a typical test taker's score differs from the average of the scores that a test taker would have gotten on all possible editions of the test. The formula used is known as Kuder-Richardson 20, or KR-20, which is equivalent to a more general formula called coefficient alpha. This involves looking at the statistical relationships among responses to individual multiple-choice questions to estimate the reliability of the total test score. Statisticians use an internal-consistency measure to calculate the reliability coefficients for the CLEP exam. The reliability coefficient can be interpreted as the correlation between the scores examinees would earn on two forms of the test that had no questions in common. 00 indicates total lack of stability, while a value of 1.00 indicates perfect stability. The reliability coefficient is intended to indicate the stability of the candidate's test scores, and is often expressed as a number ranging from. The reliability coefficient is the correlation between the scores those examinees get (or would get) on two independent replications of the measurement process. The reliability of the test scores of a group of examinees is commonly described by two statistics: the reliability coefficient and the standard error of measurement (SEM). An easier form means a higher raw score is needed to attain a given scaled score. Because the different forms of the test are not always equal in difficulty, raw-to-scale score conversions may differ from form to form. The scaled scores are reported on a scale of 20–80. Instead, it is converted into a scaled score by a process that adjusts for the level of question difficulty on the different forms of the test. The test taker's raw score is simply the number of questions answered correctly. Measuring the Reliability and Validity of CLEP ExamsĬLEP uses rights-only scoring, which means that the exams are scored without a penalty for incorrect guessing.