summative assessment and considers how inherent tensions between the different purposes of assessment may be mitigated.
The range of understanding and skill called for in the Standards acknowledges the complexity of what it means to know, to understand, and to be able to do in science. Science is not solely a collection of facts, nor is it primarily a package of procedural skills. Content understanding includes making connections among various concepts with which scientists work, then using that information in specific context. Scientific problem-solving skills and procedural knowledge require working with ideas, data, and equipment in an environment conducive to investigation and experimentation. Inquiry, a central component of the Standards, involves asking questions, planning, designing and conducting experiments, analyzing and interpreting data, and drawing conclusions.
If the Standards are to be realized, summative as well as formative assessment must change to encompass these goals. Assessment for a summative purpose (for example, grading, placement, and accountability) should provide students with the opportunity to demonstrate conceptual understanding of the important ideas of science, to use scientific tools and processes, to apply their understanding of these important ideas to solve new problems, and to draw on what they have learned to explain new phenomena, think critically, and make informed decisions (NRC, 1996). The various dimensions of knowing in science will require equally varied assessment strategies, as different types of assessments capture different aspects of learning and achievement (Baxter & Glaser, 1998; Baxter & Shavelson, 1994; Herman, Gearhart, & Baker, 1993; Ruiz-Primo & Shavelson, 1996; Shavelson, Baxter, & Pine, 1991; Shavelson & Ruiz-Primo, 1999).
As teachers fulfill their different roles as assessors, tensions between formative and summative purposes of assessment can be significant (Bol and Strange, 1996). However, teachers often are in the position of being able to tailor assessments for both summative and formative purposes.
Any activity undertaken by a student provides an opportunity for an assessment of the student's performance. Performance assessment often implies a more formal assessment of a student as he or she engages in a performance-