Source: Review of Educational Research, 80(3): 401-436. (September 2010 ).
Attention has been directed toward extended school time as a measure to improve academic achievement. The school year and day length have varied over time and across localities depending on the particular needs of the community.
Proponents argue that extending time will have learning and nonacademic benefits. Opponents suggest increased time is not guaranteed to lead to more effective instruction and suggest other costs.
Despite noted limitations in the research, past reviewers have argued that any positive relation between allocated time and achievement is tentative and instructional quality needs to be addressed first.
After a comprehensive search of the literature, 15 empirical studies of various designs conducted since 1985 were found.
The literature revealed that
(a) designs are generally weak for making causal inferences and
(b) outcomes other than achievement are scarcely studied.
That said, findings suggest that extending school time can be an effective way to support student learning, particularly
(a) for students most at risk of school failure and
(b) when considerations are made for how time is used.
Of note, the strongest research designs produced the most consistent positive results. Implications for policy and practice are discussed.