This document is a literature review discussing research on locus of control, particularly as it relates to early childhood education. Some measures of children's sense of locus of control are discussed, including the Optimism-Pessimism Test Instrument and the Stanford Preschool Internal-External Scale. A discussion of how an educator's sense of control affects his or her teaching abilities and interactions with children is included. Factors which inhibit the assessment of children's sense of locus of control are detailed, including: (1) lack of development of children's vocabulary and communication skills; (2) children's tendency to select the last possible answer offered in a structured interview situation; (3) children's tendency to respond "yes" to yes or no questions; and (4) the prevalence of a research bias which assumes that elementary school children do not have well-developed self-awareness. The review concludes by noting that locus of control appears to be an important element of children's experiences and potential success in school. As such, despite the difficulties of assessment, the concept should be more closely studied. Contains 57 references. (JW)