Generalizability Theory

Educational researchers are often interested in making inferences from what may be considered observable to that which is unobserved. Responses to items on a multiple-choice test, an argumentative essay, and other overt behaviors (e.g., number of times a child raises her hand in a classroom) are observable. Unobserved variables on the other hand are used by educational researchers to explain patterns in observations. Intelligence, personality, aptitude, and critical thinking cannot, strictly speaking, be directly observed. Such variables refer to theoretical attributes that are at best indirectly investigated. For example, a researcher may hypothesize that differences in critical thinking (i.e., unobserved) account for why some students have higher scores than others on an assignment (i.e., observable). The extent to which it is reasonable to conclude that ...