The most promising model assumes that learners develop competencies on the basis of interacting with a series of different real events or, in educational settings, simulations of those real events. In competency−based learning, the learning tasks that are performed by the students can be situated in such a simulated task environment and provide the necessary (vicarious) experience. The design of learning tasks is thus at the heart of competency−based learning or a competency−based curriculum. Second, the learning tasks will be performed more and more in technology−enhanced learning environments, posing new requirements to delivery in multimedia environments. And finally, when realistic, rich tasks are the kernel of competency−based learning such tasks must also be used for testing and assessment, asking for new approaches to diagnosing learner progress.