30/07/2025
Support Your Surgeries - The Carr-Hill Formula Campaign
The Carr-Hill formula directly impacts the financial resources available to GP practices, influencing their ability to provide services. It is a mathematical equation used to calculate the funding a GP practice receives for its core services under the GMS contract.
North Cardiff Cluster have written a letter on behalf of its patients to request an urgent review of the funding formula. This has been signed by all practices in North Cardiff Cluster.
Jeremy Miles MS
Cabinet Secretary for Health and Social Care
Welsh Government
Cardiff Bay
Cardiff
CF99 1NA
Dear Mr Miles,
We write on behalf of the 105,000 patients registered across the North Cardiff Cluster to request an urgent review of the funding formula underpinning general practice in Wales. Collectively, our GP practices receive core funding that is 20% below the national average, placing us among the lowest funded practices in the UK.
The Problem: An Outdated and Unfair Formula
Core GP funding in Wales is determined by the Global Sum Allocation formula, otherwise known as the Carr-Hill formula—a model developed in England over 25 years ago. While the original intention was fair distribution of funds according to population need, the formula in its current form fails to achieve this.
The Carr-Hill formula calculates a weighted practice population as follows:
Weighted population = actual list size × (age-s*x index × care homes index × market forces × turnover × additional needs × rurality)
A Carr-Hill index of 1.0 means a practice receives funding based on its actual (raw) patient list. In Cardiff North, the average index is just 0.8, meaning that although we care for 105,000 patients, we are funded for only 84,000. Given the current allocation of £125.20 per registered patient, this translates to an annual funding shortfall of £2.6 million.
Real-World Impact
At a cost of around £100,000 per full-time GP per year (based on BMA pay scales) this shortfall equates to approximately 135,000 fewer GP appointments annually—or 2,600 appointments each week. It is no surprise, then, that our patients sometimes struggle to get a GP appointment.
Why the Formula Is No Longer Fit for Purpose
Some elements of the Carr-Hill formula remain relevant. Adjustments for age, s*x, care home residents, and new residents (turnover) reflect reasonable differences in workload.
However, two critical components are outdated and unreliable:
1. The Additional Needs Index
Based on mortality rates and self-reported health from the late 1990s, this index has not been updated since 2004. It fails to reflect real-time chronic disease prevalence, deprivation, or demographic change.
2. The Rurality Index
Designed using English population density data, this index fails to account for Wales’s lower average density (the population density of England is approx. three time that of Wales). This particularly impacts Cardiff (population of 360,000) as for the purposes of the rurality index, it is compared to London (pop. 9 million) which significantly skews the normalisation across Wales.
Our analysis of the Carr-Hill index, WIMD data, and population age and s*x demographics across all 377 Welsh GP practices and 6,804 practices in England and Wales reveals substantial and unjustifiable funding disparities between practices serving similar populations.
In fact:
• Cardiff and Vale UHB has the lowest average Carr-Hill index (0.878) of any health board in the UK.
• All North Cardiff practices fall in the bottom 9% in the UK for core funding.
• Pontprennau Medical Centre, despite serving a population with greater than average deprivation (WIMD 582), ranks 6780 out of 6804 (Carr-Hill 0.72).
• Even Llanishen Court surgery, with the cluster’s highest Carr-Hill index (0.87), is in the bottom 9% in the UK, despite serving a significantly older-than-average population.
The Flawed Application of the Formula
The formula does not account for fixed operating costs, which make up ~55% of practice expenses (staff, premises, insurance, utilities). A Carr-Hill index of 0.8 implies that a practice can secure these inputs at 80% of their actual cost—a clear falsehood. Moreover, inflation-based uplifts in funding are also applied to the weighted list, meaning our already inadequate budgets increase at a slower rate than inflation, and existing discrepancies are compounded.
A Recognised Problem
This isn’t just a North Cardiff issue. It has been discussed at length during the recent Senedd enquiry into the future of general practice in Wales, where GPs and practice managers from across the country raised similar concerns about the accuracy and validity of the funding formula. It has also been the focus of several academic publications and media reports.
We have shared our findings with Julie Morgan MS (our local Senedd Member), Suzanne Rankin (Chief Executive, Cardiff and Vale UHB), and the Royal College of General Practitioners. All have acknowledged that this is a genuine and pressing issue that needs to be addressed.
A Cost-Neutral, Practical Request
We support wider calls to increase overall primary care investment in Wales. However, we are not asking for additional funding here. We ask only that existing funds be allocated fairly.
Specifically, we request:
1. An urgent, evidence-based review of the Global Sum Allocation formula in Wales.
2. That in the meantime, all future funding uplifts be applied to actual patient lists, not weighted populations, to prevent worsening the existing inequity.
Conclusion
This issue affects every one of our 105,000 patients. It undermines access, quality, and sustainability of care. It exacerbates pressure on 111, A&E, and secondary care. And it contributes to the wider crisis facing Cardiff and Vale UHB, currently at level 4 escalation status.
The current model is outdated, unjust, and damaging. We urge you to prioritise this issue and work with us to implement a fairer system.
Yours sincerely,
