The Bialer Scale and the Nowicki-Strickland Scale were administered twice, 4 weeks apart, to 526 students in the third through sixth grade from four public schools in a rural, predominately white, midwestern community. The association of verbal ability and the reliabilities of the locus of control scales were assessed in view of evidence that the relationship between locus of control and verbal ability may be an artifact of the reliability characteristics of the locus of control scale. Results indicated that the relationship between reliability and verbal ability may be both grade- and scale-specific. Reliability estimates both across and within grade levels for both scales were highly variable and frequently low in value. The implications for evaluation research and the possible operation of different developmental constructs that may account for differences in performance are discussed. (Author/PN)