A look at the research on extending school days, length of terms and supporting learning

According to news reports, the government is looking at a range of options to deal with any ‘lost learning’ as a result of COVID.

The measures under consideration include longer school days and shorter holidays.

The Chartered College of Teaching has looked at some of the research on this topic to support any decision and has shared this with the Department for Education. As a research-informed profession, any plans should be guided by the available research.

Summary of research

The evidence around lengthening the school day is mixed and mostly correlational rather than causal. What appears to matter most is how this time is used rather than the quantity of time.

Summer schools and extended days can be expensive, supporting teachers to do what they know best, such as delivering high-quality teaching during the time they have without additional administrative burden may be a more sustainable approach. 

Some evidence suggests that in countries where children spend longer at school, they do not necessarily perform better

“The effects from school holidays are very small on students, and there is little reason to believe that the length of the school year has much effect at all. Note that the so-called vacation effect, summer school length effect, the summer school effect, and the effect of modifying school calendars are low.”

“There is no meta-analysis of the effect of the length of the school year, but there are traditional reviews, and the effect is tiny. From the PISA results, Australia has one of the longest school days and school years across all countries, and the USA is close behind. If we take out one term/semester of 10 weeks, those countries still have more in-school time compared to Finland, Estonia, Korea, and Sweden, which all outscore Australia and the USA on PISA.” 1

Studies on longer school days found that increased instruction time can improve achievement but that the correlation depends on factors such as quality of instruction, and classroom environment.2

Whilst there is little/no correlation between allocated time and student achievement – where this time is used purposefully for academic learning there is a greater relationship with achievement.3

[1] John Hattie April 2020

The OECD echoes this: “the time spent in school is, in fact, much less important than how the available time is spent and on which field of education, how motivated students are to achieve, how strong the curriculum is and how good the teachers are,”4

This is supported by a systematic review which found that designs across the 15 reviewed studies were generally weak, making causal inferences difficult but that extending the school day can be effective, particularly for students most at risk of school failure and if considerations are made for how time is used.5

An EEF review suggests that targeted use of before and after school programmes is perhaps effective for disadvantaged pupils

“After school programmes with a clear structure, a strong link to the curriculum, and well-qualified and well-trained staff are more clearly linked to academic benefits than other types of extended hours provision.

It should be noted that there are cost and workload implications involved in having qualified teachers run these sessions. 

However, extending the school day often takes place in tandem with other school reforms so it is difficult to isolate the specific effect of the lengthened school day.6

Evidence suggests that summer schools can be effective but issues of attendance and workload

The EEF review also found summer schools with a clear academic component lead to on average two months of additional progress. “Greater impacts (as much as 4 months additional progress) can be achieved when summer schools are intensive, well resourced and involve small group tuition by trained and experienced teachers”

However – it is acknowledged that maintaining attendance can be a challenge, particularly in secondary schools.

There are also issues about who will run them and workload/opportunities for rest and recovery for teachers.

Other issues to consider

Downsides of longer school day

A House of Commons briefing report references a 2017 DfE report7 into longer school days which details the downsides of an extended school day including staff and parent concerns, such as fatigue and children travelling home alone later in the evening. While the report is on extending the day with compulsory extracurricular activities, many of the concerns are still relevant “Some school staff, parents and pupils suggested a longer day would be detrimental to pupils’ health and wellbeing, with a negative impact on the work-life balance of pupils, as well as making it more difficult for pupils to have a childhood, spend time with family or friends or do things outside of school. This was a particular concern at key stage 4 when pupils already have a busy academic schedule and extension could cause added stress. There is, therefore, a potential tension between the view that more academic provision could be targeted at those undertaking GCSEs (if this was compulsory) and the reservations of some that the same age group were those most at risk from being overstressed and hence at the need of a break from academic-related activities.”8 

Lack of evidence

Many sources cite that the quality of evidence is quite weak across studies, including a lack of control groups (e.g. Patall et al. 2010).

Impact on extracurricular activities

Extended school days could reduce opportunities for beneficial extracurricular activities including those promoting outdoor time and physical exercise. Patall et al. (2010) found that outcomes other than academic performance are rarely studied. This means that we do not know what the price for potential higher achievement may be.


Summer schools and extended days can be expensive. Sources (including EEF) point out that improving the quality of teaching and learning within the school day might be cheaper and more efficient.


Extended school days may increase fatigue and boredom and negatively impact learning.

Using the time

How the additional time is used makes a difference – is it just allocated time in school, engaged time, or academic learning time?9

  1. John Hattie April 2020
  2. National Bureau of Economic Research 2013
  3. Aronson et al, 1999
  4. OECD 2016
  5. Patall et al. 2010.
  6. EEF 2019
  7. Pages 15 and 16
  8. Extended Activity Provision in Secondary Schools – 2016 (pages 56-60)
  9. Improving Student Achievement by Extending School: Is It Just a Matter of Time? – 1999