Theoretical predictions, based on the confluence model, were made for data from six national surveys of intellectual performance, each relating intellectual performance scores to family configuration variables. The confluence model was capable of accurate prediction in all cases when three parameters were estimated. (Author/RD)

A method is proposed for the detection of item bias with respect to observed or unobserved subgroups, using a loglinear item response theory model assuming a Rasch model for ability and difficulty. A simulation study was performed with 200 sets of data to check the robustness of the method. (SLD)

In previous studies of educational systems, Markov chains have often been used in simulations in which history played no role because all events were described as independent of each other. Mono-level dynamics (i.e., the social context in which learning occurs is ignored) have also been applied to simulations. Educational theories, however, are…