system in which all students demonstrate high levels of performance, in which teachers are empowered to make the decisions essential for effective learning, in which interlocking communities of teachers and students are focused on learning science, and in which supportive educational programs and systems nurture achievement. (NRC, 1999, p. 2)
Expectations conveyed in the Standards call for assessment to meet the full range of goals for science education. To this end, a broad view of assessment is proffered, for example:
Ideas about assessments have undergone important changes in recent years. In the new view, assessment and learning are two sides of the same coin... When students engage in assessments, they should learn from those assessments. (NRC, 1999, pp. 5-6)
Assessments that resonate with a standards-based reform agenda reflect the complexity of science as a discipline of interconnected ideas and as a way of thinking about the world. Assessments must not be only summative in nature, that is, offering a cumulative summary of achievement level, usually at the end of a unit or after a topic has been covered. These summative assessments can serve multiple purposes: they help to inform placement decisions and to communicate a judgment about performance to interested parties, including parents and students. Assessment also must become an integral and essential part of daily classroom activity.
Research supports the value that the standards document places on formative assessment in enriching students' understanding of science. Black and Wiliam (1998a) define formative assessment as, “all those activities undertaken by teachers and by their students [that] provide information to be used as feedback to modify the teaching and learning activities in which they are engaged” (p. 7). They conducted a major review of more than 250 articles and books (Black & Wiliam, 1998b) that present research evidence on assessment from several countries. The main conclusion as a result of their study was as follows:
Standards are raised only by changes that are put into direct effect by teachers and students in classrooms. There is a body of firm evidence that formative assessment is an essential feature of classroom work and that development of it can raise standards. We know of no other way of raising standards for which such a strong prima facie case can be made on the basis of evidence of such large learning gains. (p. 19)
Assessment becomes formative in nature only when either the teacher or the student uses that information to inform teaching and/or to influence learning. Therefore, data from summative assessments can be used in formative ways. In practice, it may be difficult to differentiate the two, as they often begin to blur. Summative