The growing use of scales in survey questionnaires warrants the need to address how does polytomous differential item functioning (DIF) affect observed scale score comparisons. The aim of this study is to investigate the impact of DIF on the type I error and effect size of the independent samples t-test on the observed total scale scores. A…

ACT reporting categories and ACT Readiness Ranges are new features added to the ACT score reports starting in fall 2016. For each reporting category, the number correct score, the maximum points possible, the percent correct, and the ACT Readiness Range, along with an indicator of whether the reporting category score falls within the Readiness…

In adolescence research, the treatment of measurement reliability is often fragmented, and it is not always clear how different reliability coefficients are related. We show that generalizability theory (G-theory) is a comprehensive framework of measurement reliability, encompassing all other reliability methods (e.g., Pearson "r,"…

The study scrutinized the probable interaction between using cognitive test-taking strategies, reading proficiency, and reading comprehension test performance of Iranian postgraduate students, who studied English as a foreign language. The study also probed the extent to which the participants' test performance was related to the use of certain…

Study based on F. M. Lord's arguments in 1957 and 1959 that tests of the same length do have the same standard error of measurement. (CB)

A new formula is developed for the relative efficiency of two tests measuring the same trait. The formula expresses relative efficiency solely in terms of the standard errors of measurement and, surprisingly, the frequency distributions of true scores. Approximate methods for estimating relative efficiency may make this function routinely…

A simple, usefully accurate approximation of the standard error of measurement is proposed for use by classroom teachers. An empirical comparison with Lord's approximation indicated that, though not as easy to calculate as Lord's, this approximation is more practical because it is useful at any point in the score distribution. (BW)

Current usage and theory of standard error of measurement calls for one standard error of measurement figure to be used across all levels of scoring. The study revealed that scoring variance across scoring levels is not constant. As scoring ability increases scoring variance decreases. The assertion that low and high scoring subjects will…

Five of the common misuses of tests are reviewed: (1) acceptance of the test title as an accurate and complete description of the variable being measured (failure to examine the manual and the items carefully to know the specific aspects to be tested can result in misuse through selection of an inappropriate test for a particular purpose or…

Some basic statistical concepts relevant to the teacher--mean scores, standard deviation, normal and skewed distributions, z scores, item analysis, standard error of measurement, reliability--and their use by the teacher are explained. (RM)

An assumption underlying multiple linear regression is that the standard error of measurement is equal for all observations. The literature has not addressed the procedures to be used when this assumption is violated. It was clear that data analysis to be performed on districts in California would severely violate this assumption, since district…

In this comment a recent attempt by Samuel A. Livingston to develop a theory of reliability for criterion-referenced measures is critiqued. For Livingston's rejoinder see TM 500 560. (Authors/MB)

Because change is fundamental to education and the measurement of change assesses the quality and effectiveness of postsecondary education, this study examined three methods of measuring change: (1) gain scores; (2) residual scores; and (3) repeated measures. Data for the study was obtained from transcripts of 722 graduating seniors at the…

For six tests, coefficient delta as an index for internal optimality is computed. Internal optimality is defined as the magnitude of risk of the decision procedure with respect to the true score. Results are compared with an alternative index (coefficient kappa) for assessing the consistency of decisions. (Author/JKS)

The use of stepwise regression has been criticized for both interpretive misunderstandings and statistical aberrations. A major statistical problem with stepwise regression and other procedures that involve multiple significance tests is the inflation of the Type I error rate. General approaches to control the family-wise error rate such as the…