The process of reasoning from evidence can be portrayed as a triad referred to throughout this report as the assessment triangle. As shown in Figure 2–1, the corners of the triangle represent the three key elements underlying any assessment noted earlier: a model of student cognition and learning in the domain, a set of beliefs about the kinds of observations that will provide evidence of students’ competencies, and an interpretation process for making sense of the evidence.

These three elements, which are discussed in detail below, may be explicit or implicit, but an assessment cannot be designed and implemented without some consideration of each. The three are represented as corners of a triangle because each is connected to and dependent on the other two. A major tenet of this report is that for an assessment to be effective, the three elements must be in synchrony. The assessment triangle provides a useful framework for analyzing current assessment or designing future ones.

The cognition corner of the triangle refers to a theory or set of beliefs about how students represent knowledge and develop competence in a subject domain (e.g., fractions). In any particular assessment application, a theory of learning in the domain is needed to identify the set of knowledge and skills that is important to measure for the task at hand, whether that be characterizing the competencies students have acquired thus far or guiding instruction to increase learning.

FIGURE 2–1 The assessment triangle