In this self-concept scale for adolescents based on Havighurst's developmental task, the person is asked to read a paragraph which explains the task and to report the way he sees and feels about his ability to achieve the task in relation to what he can do, what others do, and what it takes to be successful at the task. Response is on a scale of from one, the poorest estimate of his ability to perform the task, to five, the highest estimate, on each of the relationships in question. After a readability test (Dale-Chall) was applied to each of the task areas, the scale was administered to 255 adolescents in grades seven through twelve in various suburban Chicago school districts. To derive validity data, the Pearson Product Moment Correlation was used to compare student to teacher responses by relationships within each task. The mean of the teacher responses was used as the criterion against which student responses were tested to derive reliability. The Kuder-Richardson 21 formula was used resulting in a coefficient of .88. Moderate correlations of the kind derived in this study place the instrument well within the acceptable range insofar as validity is concerned. Reliability is also sufficiently high to give adequate assurance of consistency in subsequent administrations. (RC)