Retest effects in matrix test performance: Differential impact of predictors at different hierarchy levels in an educational setting

If tests of cognitive ability are repeatedly taken, test scores rise. Such retest effects have been observed for a long time and for a variety of tasks. This study investigates retest effects on figural matrix items in an educational context. A short term effect is assumed for the direct retest administration in the same test session, and a long term effect is assumed for a retest interval of six months. Using multilevel modeling, we analyze if the magnitude of these effects is not only influenced by individual variation, but also by the cluster structure of students grouped within classrooms. We also investigate if the use of identical versus parallel tests has an impact on the size of the retest effects. Our main results show a negligible short term retest effect, but a large long term retest effect. Using parallel tests does not contribute to understanding individual differences in retest effects. The variation in retest effects is larger between classrooms than between students. Reasoning ability, as measured with a different test, and school grades significantly influences retest effects at the individual level, but at the classroom level, only reasoning ability is a significant predictor.     

The fit of planning methods for the part manufacturing industry,a case study

This paper investigates the specific planning environment of an automotive part manufacturer and characterizes this environment based on variables regarding the product,its demand and the manufacturing process.The fit of different planning methods,namely material requirements planning,reorder point,cyclic planning,kanban,and heijunka to this specific planning environment is analyzed and evaluated by exploratory research.The results show that different product characteristics make it hard to apply a single planning method.None of the investigated methods show the ability to cover the complex requirements of a combined planning environment of two partly divergent product types with a deep value chain.