Instruction gains value when measurement shows that objectives have been achieved and learning has occurred. Making the measurement an integral part of class activity allows the identification of problems and consequent improvements even while the course is ongoing. Learner-centered active assessment both provides direct objective measurement of learning and stimulates the use of holistic assessment tools to assess the entire learning environment. When the flow of the course is affected by active assessment results, "interactive assessment" may be a more descriptive term, implying that learner-initiated response to course materials directly effects change. Web-based technology can be a useful tool to implement a learner-centered assessment approach to enrich instruction. Online data collection has the advantage of making a faster interpretation of the results possible, allowing for an immediate and more effective course of action. (Contains 5 figures.)