Recruiting participants for studies of early-life longitudinal development is challenging, often resulting in practical upper bounds in sample size and missing data due to attrition. These factors pose risks for the statistical power of such studies depending on the intended analytic model. One mitigation strategy is to increase measurement…

A total of 72 children (including 24 educable retardates, 24 equal CA normals and 24 equal MA normals) were compared on a stimulus task under three modality switching conditions and two response modes. Error magnitudes for each testing situation are compared and implications of the results are stated. (SDH)