School Learning = f(time spent/time needed).
In 1963, John Carroll proposed a model to account for school learning. His major premise was that school learning is a function of time. To be more specific, Carroll proposed that School Learning = f(time spent/time needed).Carroll defined time spent as a function of (i.e., resulting from or composed of) opportunity and perseverance. The measure he proposed for opportunity was allocated time or the amount of time the classroom teacher made available for school learning. The measure Carroll proposed for perseverance was engagement rate or the percentage of the allocated time that students were actually on task. Allocated time was multiplied by engagement rate to produce engaged time or time on task which is defined as the number of minutes per school day that students were actually engaged in school work.