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Social Determinants of Health: Expanded In-School Learning Time


What the CPSTF Found

About The Systematic Review

The CPSTF finding is based on evidence from a systematic review of 11 studies. Five of the included studies were identified from reference lists of 2 existing systematic reviews (Patall et al., 2010, search period 1960 – 2009; Redd et al., 2012, search period not reported). The remaining 6 studies were identified through a Community Guide search for evidence (search period 2010 – February 2015).

This review was conducted on behalf of the CPSTF by a team of specialists in systematic review methods, and in research, practice, and policy related to the use of educational interventions for the promotion of health equity.

Summary of Results

More details about study results are available in the CPSTF Finding and Rationale Statement pdf icon [PDF - 299 kB].

  • Included studies reported the number of hours added to school, but provided little information on how the added time was used. This made it difficult to draw a useful conclusion.
  • Effect sizes for students’ test scores were small and inconsistent.
  • Three studies examined public charter schools that implemented other program changes in addition to expanded in-school time (Angrist et al., 2013; Dobbie et al., 2013; Hoxby et al., 2009).
    • Some of the schools provided teachers with feedback, used data to guide instruction, offered high intensity tutoring, or cultivated a culture of high expectations.
    • Taken together, these policies improved student achievement.
    • When authors looked at the effects of expanded in-school time alone, however, they found small effects.

Summary of Economic Evidence

An economic review of this intervention was not conducted because the CPSTF did not have enough information to determine if the intervention works.


Applicability of this intervention across different settings and populations was not assessed because the CPSTF did not have enough information to determine if the intervention works.

Evidence Gaps

The CPSTF identified several areas that have limited information. Additional research and evaluation could help answer the following questions and fill remaining gaps in the evidence base. (What are evidence gaps?)

  • How is added school time used?
    • Is time added as allocated school time, allocated class time, instructional time, or academic learning time?
    • Is added time used for a specific subject or across subjects?
    • Are there other changes to make use of added time, such as curriculum changes, or offers of tutoring for students in need?
  • How does this intervention apply to private schools or schools in high income communities?

Study Characteristics

  • Studies examined the effects of expanded school years and days (5 studies), expanded school years (1 study), and lengthened school days (5 studies).
  • Studies reported students’ scores on standardized tests administered at national or state levels or tests developed for the research study.
  • Studies were from the United States (9 studies), Chile (1 study), and Israel (1 study).
  • One study was conducted in a rural area.
  • Programs were implemented in public charter (5 studies), traditional (5 studies), or magnet (1 study) schools and encompassed grades K-12.
  • Programs varied in the number of hours added per school year (9 studies reporting), ranging from 90 to 300 or more hours.
  • Five of the evaluated programs were implemented in schools or school districts with high percentages of students who were black (median of 50%) or Hispanic (median 27%). The majority of students in these studies qualified for free or reduced price lunch (median 82%).