Conventional estimators for indirect effects using a difference in coefficients and product of coefficients produce the same results for continuous outcomes. However, for binary outcomes, the difference in coefficient estimator systematically underestimates the indirect effects because of a scaling problem. One solution is to standardize…

Coefficient "H" is used as an index of scalability in nonparametric item response theory (NIRT). It indicates the degree to which a set of items rank orders examinees. Theoretical sampling distributions, however, have only been derived asymptotically and only under restrictive conditions. Bootstrap methods offer an alternative possibility to…

Questions are raised concerning differences between traditional metric multiple regression, which assumes all variables to be measured on interval scales, and nonmetric multiple regression. The ordinal model is generally superior in fitting derivation samples but the metric technique fits better than the nonmetric in cross-validation samples.…

Six methods of equating Test of English as a Foreign Language (TOEFL) test scores for samples consisting of the usual groups of examinees and groups controlled for native language representation were evaluated in terms of scale stability. The equating methods included three item response theory (IRT) variants (fixed b's scaling, a one-parameter…

In 2003 the first nationally-comparable science assessment was designed, developed and carried out under the auspices of the national council of education ministers, the Ministerial Council on Education, Employment, Training and Youth Affairs (MCEETYA). In 2006 a second science assessment was conducted and, for the first time nationally, the…

In July 2001, the Ministerial Council on Education, Employment, Training and Youth Affairs (MCEETYA) agreed to the development of assessment instruments and key performance measures for reporting on student skills, knowledge and understandings in primary science. It directed the newly established Performance Measurement and Reporting Taskforce…