This report discusses the purposes and nature of various forms of assessment that can be used to enhance, support, and monitor the progress of science learning in elementary school classrooms. Chapters included are: (1) "Introduction" (describing assessment priorities); (2) "Issues in Assessment" (discussing validity, correspondence between curriculum, instruction, and test, use of results, and program assessment); (3) "Assessment of Student Learning" (dealing with the contents, methods, usages, and the attitude assessments); (4) "Assessment of Program Features" (discussing the reason, indicators, usages, targets, and self-assessment) and (5) "Improving Assessments in Elementary Science Education" (including improvement goals, starting point, and systematic approach). Eight fundamental organizing concepts for elementary school science are described and exemplified in the appendix. (YP)