Evidence base · 165 sources
The reference list.
Every [n] marker across this site corresponds to a numbered source below. Citations follow Harvard style. UK and English-language sources from 2020–2026 were prioritised; seminal earlier works are included where they are the canonical foundation for a theoretical claim.
Most-cited sources
Primary references.
The 16 sources cited most frequently across the site, reproduced here in full. The complete 165-source list is available in the full business case document on request.
[1]
Department for Education (2025). School Workforce in England, Academic Year 2023/24. UK Government. Available at: www.gov.uk/government/statistics/school-workforce-in-england-2024. [Cited for absence rates, FTE teacher count, days lost.]
[2]
Department for Education (2025). Schools, Pupils and their Characteristics, 2024/25. UK Government. [Cited for academy sector proportion, SEND prevalence.]
[5]
Department for Education (2024). Use of Supply Teachers in Schools: Research Report. UK Government. [Cited for agency mark-ups, non-specialist cover, QTS issues, supply-teacher experience of class context.]
[6]
Department for Education (2024). Working Lives of Teachers and Leaders, Wave 2. UK Government. [Cited for leader working hours, proportion considering leaving, workload data.]
[7]
Department for Education (2025). Keeping Children Safe in Education 2025. UK Government. [Cited for statutory induction requirements, paragraph 100, Single Central Record.]
[9]
Department for Education (2024). National Behaviour Survey 2022/23. UK Government. [Cited for lesson time lost to low-level disruption, 25% figure for 10+ minutes per 30-minute lesson.]
[33]
Education Endowment Foundation (2019). Improving Behaviour in Schools: Guidance Report. EEF. [Cited for evidence that consistency of behaviour-policy application by all adults is the single biggest cover lever.]
[35]
Ofsted (2014). Below the Radar: Low-level Disruption in the Country's Classrooms. UK Government. [Cited for up-to-38-days-per-year figure for teaching lost to low-level disruption.]
[46]
Borgen, N.T., Markussen, S. and Raaum, O. (2023). 'Socioeconomic differences in the long-term effects of teacher absence on student outcomes', European Societies, 25(5), pp. 628–653. [Cited for −2.3% SD exam-grade finding; concentrated on low-SES pupils; dropout probability.]
[47]
Miller, R.T., Murnane, R.J. and Willett, J.B. (2008). 'Do teacher absences impact student achievement? Longitudinal evidence from one urban school district', Educational Evaluation and Policy Analysis, 30(2), pp. 181–200. [Cited for 1.7–3.3% SD maths impact per 10 additional absence days.]
[71]
Hattie, J. (2009). Visible Learning: A Synthesis of Over 800 Meta-analyses Relating to Achievement. Routledge: London. [Cited for teacher quality as the largest in-school determinant of pupil outcomes.]
[79]
Shulman, L.S. (1986). 'Those who understand: knowledge growth in teaching', Educational Researcher, 15(2), pp. 4–14. [Cited for the concept of pedagogical content knowledge; the theoretical foundation for lesson-handover as a tool.]
[83]
Sweller, J. (1988). 'Cognitive load during problem solving: effects on learning', Cognitive Science, 12(2), pp. 257–285. [Cited for working-memory limits (~4–7 chunks); the theoretical foundation for extraneous-load reduction in the cover briefing.]
[85]
Rosenshine, B. (2012). 'Principles of instruction: research-based strategies that all teachers should know', American Educator, Spring 2012. [Cited for the ten principles of effective instruction; the observation that each presupposes class-specific knowledge.]
[86]
Bandura, A. (1977). 'Self-efficacy: toward a unifying theory of behavioral change', Psychological Review, 84(2), pp. 191–215. [Cited for the four sources of self-efficacy; the theoretical foundation for structured information as a scaffold.]
[101]
Ronfeldt, M., Loeb, S. and Wyckoff, J. (2013). 'How teacher turnover harms student achievement', American Educational Research Journal, 50(1), pp. 4–36. [Cited for spillover effects of teacher instability on the whole school organisation; concentration on disadvantaged pupils.]
[111]
Schools Week (2026). 'Supply staff agency fee caps introduced under new DfE framework.' [Cited for DfE fee-cap framework; caps on daily supplier fees between £32 and £55.]
[134]
OECD (2023). PISA 2022 Results, Volume II: Learning During — and From — Disruption. OECD Publishing: Paris. [Cited for 54% of England principals reporting staffing shortages affect teaching; OECD average 47%.]
[151]
Cook, C.R. et al. (2018). 'Positive greetings at the door: evaluation of a low-cost, high-yield proactive classroom management strategy', Journal of Positive Behavior Interventions, 20(3), pp. 149–159. [Cited for ~9 percentage point reduction in disruptive behaviour and ~20 percentage point improvement in academic engagement when adults knew pupils' names.]
[165]
Ofsted (2024). School Inspection Handbook. UK Government. [Cited for the provision that an "ineffective safeguarding" judgement can produce an inadequate overall Ofsted rating regardless of other strengths.]
Full evidence base
The complete 165-source list.
The full reference list — spanning UK statutory guidance, official statistics, peer-reviewed journals indexed in Web of Science, Scopus and ERIC, and reports from established research institutes — is reproduced in the 68-page business case document. Available to policy teams, investors, and governance committees on request.