Numerous diagnostic studies have been conducted on large-scale assessments to illustrate the students' mastery profile in the areas of math and reading; however, for science a limited number of investigations are reported. This study investigated Iranian eighth graders' competency mastery of science and examined the utility of the General…

A general program for item-response analysis is described that uses the stabilized Newton-Raphson algorithm. This program is written to be compliant with Fortran 2003 standards and is sufficiently general to handle independent variables, multidimensional ability parameters, and matrix sampling. The ability variables may be either polytomous or…

Latent class models for cognitive diagnosis often begin with specification of a matrix that indicates which attributes or skills are needed for each item. Then by imposing restrictions that take this into account, along with a theory governing how subjects interact with items, parametric formulations of item response functions are derived and…

Psychological tests often involve item clusters that are designed to solicit responses to behavioral stimuli. The dependency between individual responses within clusters beyond that which can be explained by the underlying trait sometimes reveals structures that are of substantive interest. The paper describes two general classes of models for…

The International Adult Literacy Survey (IALS) was conducted in 1994 in seven European countries with the aim of producing literacy profiles to be used in individual national analyses as well as in international comparisons. It was assumed that the test items could be divided into three unidimensional scales corresponding to the aspects…