Enhancing Modularity and Feedback in Computer Aided Assessment

We present a model of a computer aided assessment system - CATS (computer assessable task system) - for mathematics, which is both modular and has rich feedback. Modular in the sense that elaborated tasks need not be built from scratch but, instead, from already existing tasks. Modules are made general enough to be reusable in many different contexts. As a consequence, the construction and management of multiple-step problems with complex system-user interaction, is facilitated for non-expert users. By rich feedback we mean that the system automatically generates messages explaining errors, whenever students make algebraic manipulation and logical mistakes. This contrasts with current assessment software where feedback must be hard coded by the teacher, therefore constraining feedback richness by the teacher programming skills