Varied attempts by educators to individualize the instructional process in a classroom setting are quite frequently hindered or facilitated by the vertical pattern of organization--graded or nongraded--under which a given school functions. The nongraded school allows for the progression of a student through the contents of a given subject independent of any fixed time boundaries. By virtue of its concern with the time factor in learning, John B. Carroll's model of school learning appears to be a viable theoretical basis for making decisions regarding the facilitation of individualized instruction via school organizational patterning. In this study the Carroll model was (a) utilized as a framework for individualizing instruction in a nongraded setting and (b) investigated as a theoretical basis for educational decisions relative to individualized instructional strategies and school organizational patterning. Measures of degree of learning and perseverance were recorded under two levels of quality of instruction and three levels of ability to understand instruction. The employment of a mastery learning strategy encompassing feedback/correction procedures served to differentiate between the two treatments. The findings of the investigation supported Carroll's hypothesized interaction as well as additional hypotheses inherent within the model. (Author)