The NHS has significantly expanded its workforce in recent years, yet patients continue to face historically long waits for planned surgery. A new study finds that staff sickness absence and instability in administrative teams – not workforce size per se – as key factors, researchers report in the Journal of the Royal Society of Medicine today.
The study, by researchers from the University of Oxford, Heriot-Watt University, the University of Edinburgh, and Brunel University of London, found that elective surgery waiting lists rose almost threefold from 2.6 million in 2013 to 7.7 million by early 2024. While the list has since fallen from its peak, it remains historically high.¹
Despite the addition of roughly 250,000 full-time equivalent staff between 2018 and 2023, the National Institute for Health and Care Research (NIHR)-supported research shows the average number of completed procedures per clinical staff member fell by around four per cent between 2018 and 2023, equivalent to roughly 3 fewer procedures per clinician per year, depending on specialty.
"You'd think that more staff should mean more patients treated, but that's not what the data show," said Associate Professor Catia Nicodemo, a health economist at the University of Oxford's Nuffield Department of Primary Care Health Sciences and Brunel University of London. "When doctors are off sick and there aren't enough administrators to schedule operations and process referrals, the system slows down regardless of headcount."
The study analysed monthly data of England NHS Trusts between January 2018 and December 2023. Staff sickness absence had a consistent and significant effect: each one percentage point rise in medical workforce sickness rates was associated with a 4.4 per cent fall in completed elective cases. Sickness rates rose from 4.3 per cent in 2018 to 5.0 per cent in 2023.
"When a doctor is off sick, you don't just lose one person – you lose the operations they would have done, the patients who then stay on the waiting list longer, and the knock-on pressure on colleagues who are still at work," said Professor Cristina Tealdi, an economist at Heriot-Watt University. "The effects compound across the system."
Administrative staffing also mattered. Trusts with more stable and better-resourced administrative teams cleared backlogs markedly faster – with greater admin stability associated with backlogs shrinking by 14.4 per cent relative to completed operations. The researchers argue that the people who schedule operations, manage referrals, and coordinate patient flow play a larger role in clearing waiting lists than is commonly recognised. By contrast, the turnover of doctors joining and leaving Trusts had no significant effect.
Trusts serving older populations faced additional pressure. A one percentage point increase in the local share of people aged 70 and over was associated with a 13 per cent decline in completed cases, likely reflecting the greater clinical and administrative complexity involved in treating older patients.
The findings speak directly to the government's 10 Year Health Plan for England, which explicitly commits to reducing NHS sickness absence rates alongside its broader shifts from hospital to community and from treatment to prevention.² The 2025 NHS Staff Survey, published in March 2026, suggests the challenge remains urgent: 31.5 per cent of staff reported feeling burned out due to their work, up from 30.3 per cent the previous year, and confidence that employers would act on wellbeing concerns fell.³ With the government's 10 Year Workforce Plan expected later this year, the researchers argue this evidence should inform its priorities.⁴
"Staff sickness absence isn't a sign of a lazy workforce – it's a symptom of a system under immense strain," said Professor Sir Aziz Sheikh, Head of the Nuffield Department of Primary Care Health Sciences at the University of Oxford. "The government's forthcoming Workforce Plan offers a clear moment to act on this evidence – by addressing the working conditions that drive burnout and sickness, and ensuring there are enough administrators to keep hospitals running smoothly."
The authors note that the study is observational, based on Trust-level administrative data, and relates specifically to elective surgery rather than urgent, emergency, or outpatient care. The findings should be interpreted as identifying important associations rather than proving direct cause and effect.
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¹ As of January 2026, the NHS elective waiting list stood at 7.25 million cases. NHS England, "NHS waiting list lowest in almost 3 years as NHS battled busiest winter on record," 13 February 2026. https://www.england.nhs.uk/2026/02/waiting-list-lowest-3-years-battled-busiest-winter-on-record/
² The 10 Year Health Plan, "Fit for the Future," was published on 3 July 2025. The plan commits to "reduce the NHS's sickness rates from its current rate of 5.1 per cent." NHS Employers, "Understanding the workforce implications in the 10 Year Health Plan," 3 September 2025. https://www.nhsemployers.org/news/understanding-workforce-implications-10-year-health-plan
³ NHS Staff Survey 2025 national results. NHS Employers, "NHS Staff Survey 2025: health and wellbeing overview," 12 March 2026. https://www.nhsemployers.org/articles/nhs-staff-survey-2025-health-and-wellbeing-overview
⁴ At time of writing, the 10 Year Workforce Plan is expected in Spring 2026. NHS Employers, "Understanding the workforce implications in the 10 Year Health Plan," 3 September 2025. https://www.nhsemployers.org/news/understanding-workforce-implications-10-year-health-plan. See also House of Commons Library, "The 10 Year Health Plan for England," 18 March 2026. https://commonslibrary.parliament.uk/research-briefings/cbp-10368/