What works at key stage 4 in terms of improving GCSE outcomes, two or three years of study?

Helen Poet, Chris Morton, Simon Rutt, Afrah Dirie, Megan Lucas and Matthew Walker

18 November 2022

Research report on the EEF website

This study was funded from the Education Endowment Foundation’s 2019 ‘School Choices’ round. It aimed to investigate the extent of, and rationale for, offering a two- or three-year KS4 in England and explore how the choices made by schools on their length of KS4 affected pupil outcomes at GCSE.

This was a quasi-experimental study that used a matched comparison group, difference-in-differences approach. A total of 405 schools responded to a survey exploring KS3 and KS4 length for their Year 9, 10, and 11 students. The impact analysis included 104 of these schools (170,675 pupils); the data was matched to the National Pupil Database for analysis. The number of schools in the sample has implications for the analysis and interpretation. The study compared existing practices in schools rather than implementing a specific intervention.

The survey data and impact analysis concern the pre-Covid period, but some information about how Covid related disruption had influenced the curriculum was gathered during the interviews.

Key Findings

  • Almost two-thirds of the 405 schools that responded to the survey (65%) operated a three-year KS4 for at least some subjects, while around a third of responding schools had a two-year KS4 (35%). There was a wide variety in the way schools organised their KS3/KS4.
  • Schools running a three-year KS4 were motivated to do so by requirements of the new GCSEs and, to a lesser extent, to improve pupil engagement in Year 9. In contrast, schools that had maintained a two-year KS4 described their primary motivation as the importance of a strong curriculum and breadth of experience at KS3 when delivered over three years. Schools did not perceive a one-size-fits-all approach to KS3 and KS4 delivery and the participating schools had tailored their curriculum with the aim of best-serving their pupils. 
  • Schools were offering - and pupils were taking - fewer qualifications at the end of KS4; this was the case in both shorter and longer KS4 schools and had declined from a peak in 2011/2012 to the time of the survey in 2019/20. The analysis indicated that this shift was driven by policy changes relating to school-level performance measures, such as the EBacc, and changes to the way vocational qualifications contribute to school tables.
  • The research is unable to conclude that any differences in observed outcomes are due to the length of KS4. This is because it was not possible to achieve a strong match through the QED, with the two groups of schools on different GCSE performance trajectories prior to the KS4 length policy change. This caveat applies to the primary outcome (maths attainment), the secondary outcomes (English literature and 5 A*-C grades at GCSE), and to a subgroup analysis on the maths performance of FSM pupils. Therefore we cannot conclude that any differences in attainment are due to the policy change and may instead be caused by other factors instead of, or in addition to, changing the length of KS4. The recommendation is that schools should not make a decision about the length of their KS4 on the basis of the impact evaluation findings reported.