This digest discusses sources of error in testing, several approaches to estimating reliability, and several ways to increase test reliability. Reliability has been defined in different ways by different authors, but the best way to look at reliability may be the extent to which measurements resulting from a test are characteristics of those being…

Considers the situation in which content or administrative considerations limit the way in which a test can be partitioned to estimate the internal consistency reliability of the total test score. Demonstrates that a single-valued estimate of the total score reliability is possible only if an assumption is made about the comparative size of the…

This study applies a procedure which yields estimates of true score change on the Scholastic Aptitude Test (SAT) adjusted for regression effects and student self-selection. It is shown that student self-selection in deciding to repeat an admissions test probably involves factors in addition to the measurement error attributable to variations in…

Student self-selection in deciding to repeat a test was examined by contrasting the test performance of students taking the Scholastic Aptitude Test (SAT) as juniors and again as seniors with the test performance of students taking the SAT only once as juniors. Results suggest there is self-selection in test repetition. (Author/GK)

Reliability coefficients of linear combinations of observed scores have anomalous properties which have led to difficulties in the investigation of difference scores and gain scores in test theory. Discrepancies between classical results and correct results obtained from more general formulas, which allow for correlated errors, are examined…

The test performance of students who took the Scholastic Aptitude Test (SAT) only once as juniors was contrasted with students who took the test as juniors and again as seniors. Estimates of expected test performance on a common initial administration in the junior year were derived from separate equating sections and background variables.…

A solution is offered to problems associated with the inequality in the manipulability of probabilities of classification errors of masters versus nonmasters, based on competency test results. Eschewing the typical arbitrary establishment of observed-score standards below 100 percent, the solution incorporates a self-correction of wrong answers.…

Wechsler Adult Intelligence Scale-Revised protocols from two vocational counseling clients were scored by 19 psychologists and 20 graduate students. Regardless of scorer's experience level, mechanical scoring error produced summary scores varying by as much as 4 to 18 IQ points. (Author/RC)

The importance of using the standard error of measurement (SEm) in determining reliability in test scores is emphasized. The SEm is compared to the hypothetical true score for standardized tests, and procedures for calculation of the SEm are explained. (JDD)

Improvements are made on previous estimates for the conditional standard error of measurement in prediction, the conditional standard error of estimation (CSEE), and the conditional standard error of prediction (CSEP). Better estimates of how test length affects CSEE and CSEP are derived. (SLD)

Errors in oral reading tests result from inaccuracies that tend to creep in because children are not totally consistent while taking a test and from inaccuracies caused when the examiner does not catch a word recognition error, giving credit for an answer that is more wrong than right or vice versa. Every test contains a standard error of…

This paper discusses standard error of measurement (SEM), the amount of variation or spread in the measurement errors for a test, and gives information needed to interpret test scores using SEMs. SEMs at various score levels should be used in calculating score bands rather than a single SEM value. (SLD)

With the increasing globalization of human resources practices, a commensurate increase in demand has occurred for multi-language ("global") personality norms for use in selection and development efforts. The combination of data from multiple translations of a personality assessment into a single norm engenders error from multiple sources. This…

This study is an attempt at a cohesive characterization of the concept of essay reliability. As such, it takes as a basic premise that previous and current practices in reporting reliability estimates for essay tests have certain shortcomings. The study provides an analysis of these shortcomings--partly to encourage a fuller understanding of the…

If a loss function is available specifying the social cost of an error of measurement in the score on a unidimensional test, an asymptotic method, based on item response theory, is developed for optimal test design for a specified target population of examinees. Since in the real world such loss functions are not available, it is more useful to…