Measuring understanding is notoriously difficult. Indeed, in formulating learning outcomes the word 'understanding' is usually avoided, but in the sciences, developing understanding is one of the main aims of instruction. Scientific knowledge is factual, having been tested against empirical observation and experimentation, but knowledge of facts…

Instructors can use both "multiple-choice" (MC) and "constructed response" (CR) questions (such as short answer, essay, or problem-solving questions) to evaluate student understanding of course materials and principles. This article begins by discussing the advantages and concerns of using these alternate test formats and…