The use of paper and pencil, videotape recordings, and microcomputers in student testing provide three very different views of student achievement. Paper and pencil tests can record how students compose tests and documents, and how they critique documents or performances. Video recordings can record how students explain ideas, answer questions, listen in class, cooperate in a joint task, and perform experiments. Microcomputers can record how students learn with feedback, trace their thinking processes, and record their abilities to deal with realistic situations. The construction of tests and the format those tests take are based, in part, on the kinds of tasks that students are required to learn to perform and a change in educational testing affects the instructional material that is taught. A key part of a current effort to develop systemically valid methods of assessing student performance in the context of high school science is the exploration of the kinds of tasks that will enable students to use and demonstrate the broader range of abilities outlined above, which will require very different kinds of tasks than those that are now the norm. Data are being collected for this project using a computer program called Physics Explorer, which provides students with a simulation environment in which they can conduct experiments to determine how different variables affect each other in a physical system. Another kind of task might be diagnosing why a system is not behaving as expected. Computers can also provide a setting where students can carry out a design task and try it out in a simulation. Research needs to be conducted to test this new approach to testing in schools, paying particular attention to its reliability, generalizability across schools, and effectiveness. (17 references) (DB)