Social Determinants of Health: Year-Round Schooling

Summary of CPSTF Finding

The Community Preventive Services Task Force (CPSTF) finds insufficient evidence to determine whether year-round schools improve academic achievement. Academic achievement is an established determinant of long-term health.

The evidence on effectiveness of single-track year-round schools is insufficient because the role of intersession programs is unclear. Intersession programs are offered between regular school sessions and may be used for remedial or accelerated course work.

The evidence for multi-track year-round schools is also insufficient. If these programs are implemented, it is important that students be equitably assigned to tracks that have equivalent resources.


Year-round schooling alters the school calendar by redistributing school and vacation days more evenly throughout the year, without changing the number of school days per year.

There are two forms of year-round schooling:

  • Single-track: all students participate in the same school calendar. In place of long breaks such as summer vacation, shorter breaks are distributed more evenly throughout the year. Schools may offer intersession programs with remedial or accelerated classes. Single-track programs are generally implemented to address the problems of summer loss and achievement gaps.
  • Multi-track: students are grouped into “tracks” and each one has its own schedule. There is always one track on break while the others are in session, and breaks are distributed throughout the year. Except for certain holidays, schools remains open year-round. Multi-track programs are generally implemented to address school crowding and take advantage of school facilities that are closed and empty during summer.

CPSTF Finding and Rationale Statement

Read the full CPSTF Finding and Rationale Statement for details including implementation issues, possible added benefits, potential harms, and evidence gaps.

Promotional Materials

About The Systematic Review

The CPSTF finding is based on evidence from a meta-analysis published in 2003 (Cooper et al., 47 studies, search period January 1965 March 2002) combined with more recent evidence (6 studies, search period March 2002 August 2016).

Of the 47 studies from the meta-analysis, 23 specified whether the calendar was single- or multi-track. In combination, 18 studies evaluated single-track year-round calendars and 11 evaluated multi-track year-round calendars. One study (Graves 2010) is counted twice because it evaluated both single- and multi-track programs, and another study (Wu et al., 2010) is not included because it evaluated both single- and multi-track programs together.

The systematic 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 promoting health equity.


Students may lose the equivalent of two months of grade-level learning over a summer break (Cooper et al., 1996). This loss is greater among economically disadvantaged students. Schools may be able to address this problem by shortening the summer break and redistributing vacations and breaks throughout the school year.

Summary of Results

More details about study results are available in the CPSTF Finding and Rationale Statement.

Cooper et al. meta-analysis

  • Studies of single-track year-round calendars showed small and consistent improvements in standardized achievement test scores (15 studies)
  • Studies of multi-track year-round calendars showed inconsistent results for standardized achievement test scores (8 studies)
  • There was no significant difference of effect between studies that did and did not include intersession programs

Evidence from the updated search

  • Studies of single-track year-round calendar reported mixed findings (3 studies). The role of intersession in single-track programs was not clear.
  • Studies of multi-track year-round calendar reported mostly negative outcomes (3 studies).

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 single-track and multi-track year-round schools across different settings and populations was not assessed because the CPSTF did not have enough information to determine if these interventions work.

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?)
  • Is there an optimal spacing of school days and breaks for purposes of learning?
  • Does optimal spacing match a particular calendar design?
  • Single-track calendars
    • Are single-track calendars effective in the absence of intersession programs? Does the intersession account for the benefit of single-track calendars?
  • Multi-track calendars
    • How is track placement achieved and how can equity be assured?

Study Characteristics

  • Outcomes included student scores on standardized tests administered at national or state levels.
  • All studies were conducted in the United States.
  • In the Cooper et al. meta-analysis, year-round schooling was implemented in elementary (23 studies) and secondary (9 studies) schools in urban (18 studies), suburban (6 studies), and rural (5 studies) school districts.
  • In studies from the updated search, year-round schooling was implemented in elementary schools (3 studies), high schools (1 study), and a combination of elementary, middle and high schools (2 studies). Three studies evaluated interventions in mixed urban/suburban or rural (3 studies) settings, and 3 studies did not report this information.

Analytic Framework

Effectiveness Review

Analytic Framework

When starting an effectiveness review, the systematic review team develops an analytic framework. The analytic framework illustrates how the intervention approach is thought to affect public health. It guides the search for evidence and may be used to summarize the evidence collected. The analytic framework often includes intermediate outcomes, potential effect modifiers, potential harms, and potential additional benefits.

Summary Evidence Table

Effectiveness Review

Summary Evidence Table Studies From the Updated Search (March 2002-August 2016)
Refer to Cooper, et al. (2003) for evidence from the published systematic review.

Included Studies

The number of studies and publications do not always correspond (e.g., a publication may include several studies or one study may be explained in several publications).

Effectiveness Review

Brown J, Sarte S, Francis K, Rest G, Reynolds D; Joint Legislative Audit and Review Commission. Report To the Governor and The General Assembly of Virginia: Review of Year-Round Schools; October 2012; Richmond, Virginia. Available from URL:

Graves, J. The academic impact of multi-track year-round school calendars: a response to school overcrowding. J Urban Econ 2010;67:378 91.

Mitchell RE and Mitchell DE. Student segregation and achievement tracking in year-round schools. Teachers College Record 2005;107(4):529 62.

McMullen SC. The impact of year-round schooling on academic achievement: evidence from mandatory school calendar conversions. American Econ J 2012;4(4):230 52.

Ramos BK. Breaking the tradition of summer vacation to raise academic achievement. ERS Spectrum 2011;29(4):1-20.

Wu AD. Does Year Round Schooling Affect the Outcome and Growth of California’s API Scores? J Educ Res & Policy Studies 2010;10(1):79 97.

Additional References Related to the Included Studies

Graves J. Effects of year-round schooling on disadvantaged students and the distribution of standardized test performance. Econ Educ Rev 2011;30:1281 305.

McMullen SC, Rouse KE, Haan J. The distributional effects of the multi-track tear-round calendar: a quantile regression approach. Applied Econ Letters 2015;22(15):1188 92.

Search Strategies

Effectiveness Review

The Community Preventive Services Task Force finding is based on evidence from a systematic review published in 2003 (Cooper et al., search period through March 2002, 47 studies) and a Community Guide update (5 studies; search period March 2002-August 2016). To update the search, the review team used the search strategy listed below.

The following databases were searched for English-language papers that evaluated the impact of modified school time programs:

  • ERIC
  • PsycINFO

The literature search covered interventions modifying school time by either expanding school time or rearranging school calendar to create year-round schooling without expanding school time. For the review on year-round schooling, Community Guide staff limited the search to databases used by Cooper et al (except for Dissertation Abstracts, which was excluded because we did not include dissertations in the update).

Following are the search strategies used for this review.


Date Searched: 8/4/2016

Search Strategy

Limits applied after March 2002, English only, exclude dissertations/theses

S15 1 OR 2 OR 3 OR 4 OR 5 OR 6 OR 7 OR 8 OR 9 OR 10 OR 11 OR 12 OR 13 OR 14

S14 “lengthening the school year”

S13 “lengthen the school year”

S12 “lengthened school year”

S11 “longer school year”

S10 “extended school year”

S9 “extended school calendar”

S8 “year round education” OR “year-round education”

S7 “modified school calendar”

S6 “alternative calendar” OR “alternative calendars” OR “alternative school calendar” OR “alternative school calendars”

S5 “year round school”

S4 “twelve month calendar”

S3 “extended school year”

S2 SUBJECT.exact(“Year Round Schools”)

S1 “12 month school” OR “twelve month school”

Database: PsycINFO (OVID)

Date Searched: 8/4/2016

Search Strategy
  1. (alternative calendar or modified school calendar or year-round school).mp.
  2. (year-round education or 12 month school or twelve month school or extended school calendar*).mp.
  3. (longer school year or extended school year or lengthened school year or lengthen the school year).mp.
  4. (lengthening the school year or alternative school calendar).mp.
  5. (lengthening school year or lengthen* the school year or alternative school calendar*).mp.
  6. (200204* or 200205* or 200206* or 200207* or 200208* or 200209* or 20021*).up.
  7. (2003* or 2004* or 2005* or 2006* or 2007* or 2008* or 2009* or 2010* or 2011* or 2012* or 2013* or 2014* or 2015* or 2016*).up.
  8. 6 or 7
  9. or/1-5
  10. 8 and 9

Review References

Cooper H, Valentine JC, Charlton K. The effects of modified school calendars on student achievement and on school and community attitudes. Review of Educational Research 2003 73(1):1-52

Cooper H, Nye B, Charlton K. The effects of summer vacation on achievement test scores: a narrative and meta-analytic review. Review of Educational Research 1996;66(3):227-68.

Graves J. The academic impact of multi-track year-round school calendars: a response to school overcrowding. J Urban Econ 2010;67:378-91.

Wu AD, Stone JE. Does year round schooling affect the outcome and growth of California’s API scores? J Educ Res & Policy Studies 2010;10(1):79-97.

Considerations for Implementation

Despite the finding of insufficient evidence, the following are considerations for implementation drawn from studies included in the evidence review, the broader literature, and expert opinion.
  • Before implementing year-round schooling, schools and school district should consider the following issues.
    • Parental employment and how it will be affected
    • Child care availability
    • School administration challenges
    • Use of intersessions
  • Year-round schooling can make it more difficult for families to schedule extra-curricular activities and vacations.
  • Multi-track calendars
    • Potential benefits of year-round use of the school building include decreases in school vandalism and cost savings or cost delays for the school district.
    • Coordinating school administration and scheduling is complex.
    • It can be difficult to schedule standardized testing and after-school activities.
    • Students may be separated from their friends who are in different tracks.
    • Steps must be taken to assure students are equitably distributed among all tracks. Some of the included studies reported that lower income and minority students were more often assigned to poorly supported tracks.