Science educators and other are faced with determining what changes must be made in education to insure scientific literacy for all students. One area that has been identified as playing a crucial role in science achievement outcome is assessment. This monograph focuses on improving assessment techniques used by teachers as they devise tests to measure and evaluate the outcomes of science instruction in their classrooms. The following chapters are included to provide insight on the role of assessment in science education reform: (1) "Assessing Science Achievement in the Middle Schools"; (2) "A Framework for Teaching and Assessing Science: The Nature of Science and the Nature of the Learner"; (3) "Assessing Levels of Cognition in the Content Areas of Science"; (4) "Assessing Process Skills: Scientific Thinking, Inquiry and Problem Solving"; and (5) "Authentic Assessment in Science: Performing Like a Scientist." The latter half of the document is composed of appendices, that contain illustrative items in the cognitive domain, scientific problem solving, and authentic assessment tasks proficiency profiles for science process skills. (ZWH)