other education stakeholders the nature of their accomplishments and the progress of their learning.

CONCLUSIONS

The Nature of Assessment and Reasoning from Evidence

This report addresses assessments used in both classroom and largescale contexts for three broad purposes: to assist learning, to measure individual achievement, and to evaluate programs. The purpose of an assessment determines priorities, and the context of use imposes constraints on the design. Thus it is essential to recognize that one type of assessment does not fit all.

Often a single assessment is used for multiple purposes; in general, however, the more purposes a single assessment aims to serve, the more each purpose will be compromised. For instance, many state tests are used for both individual and program assessment purposes. This is not necessarily a problem, as long as assessment designers and users recognize the compromises and trade-offs such use entails.

Although assessments used in various contexts and for differing purposes often look quite different, they share certain common principles. One such principle is that assessment is always a process of reasoning from evidence. By its very nature, moreover, assessment is imprecise to some degree. Assessment results are only estimates of what a person knows and can do.

Every assessment, regardless of its purpose, rests on three pillars: a model of how students represent knowledge and develop competence in the subject domain, tasks or situations that allow one to observe students’ performance, and an interpretation method for drawing inferences from the performance evidence thus obtained. In the context of large-scale assessment, the interpretation method is usually a statistical model that characterizes expected data patterns, given varying levels of student competence. In less formal classroom assessment, the interpretation is often made by the teacher using an intuitive or qualitative rather than formal statistical model.

Three foundational elements, comprising what is referred to in this report as the “assessment triangle,” underlie all assessments. These three elements—cognition, observation, and interpretation—must be explicitly connected and designed as a coordinated whole. If not, the meaningfulness of inferences drawn from the assessment will be compromised.

The central problem addressed by this report is that most widely used assessments of academic achievement are based on highly restrictive beliefs about learning and competence not fully in keeping with current knowledge about human cognition and learning. Likewise, the observation and interpretation elements underlying most current assessments were created



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