ABSTRACT
This chapter discusses the application of measurement principles to the theory and practice of classroom formative assessment. It describes assessment generally—and formative assessment particularly—from the perspective of evidentiary reasoning. The chapter explains how principles from educational measurement and the practice of formative assessment might be brought together. The development and application of evidentiary reasoning to assessment comes primarily from the work of Mislevy and colleagues on Evidence Centered Design. That model weights evidence according to its value, generating a score, a qualitative characterization, or both. That measurement model also provides an estimate of the uncertainty associated with that score or characterization. When formative assessment is embedded in educational software, formal measurement models can be employed because student responses can be automatically captured, the responses used in characterizing underlying proficiencies, and those characterizations acted upon to adjust instruction.
