Student Achievement

Time that students spend engaged in learning is known in the literature as “time on task.” A substantial body of research has long identified quantity of time on task by itself as a key determinant of student performance on an individual level.

The conceptual framework connecting time and learning began in 1963 with the publication of “A Model of School Learning” by educational psychologist John Carroll. In his formulation, Carroll demonstrated that the “degree of learning” that any individual achieves rests on the ratio between time needed to achieve that degree of learning and the time spent learning. Since then, many studies have validated Carroll’s theory.

In recent years, a number of scholars have sought to identify particular practices and policies that correlate to higher student outcomes. These researchers have found that greater time in school is strongly associated with better student performance, on both an individual and a school level. For example:

  • A study from Harvard economist Roland Fryer examined charter schools of New York City to identify those elements within schools that have the greatest impact on academic outcomes. Fryer determined that instructional time of at least 300 more hours than the conventional district calendar is one of the strongest predictors of higher achievement (along with high-dosage tutoring, consistent feedback to teachers, use of data, and high expectations). 
  • Using essentially the same data set, Stanford University economist Caroline Hoxby employed a multivariate analysis to identify how strongly specific school policies—from board composition to curricular choices to school structures—correlate with student outcomes. Hoxby and her colleagues found that total learning time was one of the strongest predictors of student outcomes.
  • In a mixed-methods study designed to understand why middle school students in four Boston charter schools significantly outperformed students in district middle schools, the American Institute of Research reported that one of the major structural differences between the two types of schools was their hours of operation. 
  • A meta-analysis of schools that had extended days and/or years found that adding time was, more often than not, associated with improved school-wide outcomes, noting stronger effects among schools serving primarily at-risk students. 

To access more research on expanded learning time and student achievement, we recommend the NCTL publication The Case for Improving & Expanding Time in School: A Review of Key Research & Practice