Larger GP practices may deliver more appointments, but are they the most efficient way to provide good care?

GP practices are getting bigger. In 2004, there were around 9 thousand GP practices in England. Mergers and takeovers mean that today there are around 6,200. One in five of these practices now serve more than 14,000 patients. The trend looks set to continue as practices seek to reconcile increased demand, recruitment challenges, and funding pressures. Market forces, competition, and technology are also in the mix. Previous studies have examined the relationship between practice size and service quality, care continuity, consultation length, patient experience and patient reported outcomes, with mixed conclusions. Towards the end of last year, two papers were published that examined the impact of practice size on the productivity or efficiency of primary medical services. So, do many hands make light work, or do too many cooks spoil the broth?

In November 2025, Augustine Onwunduba and colleagues at Queen Mary University published a paper that explored the relative efficiency of more than 5,000 practices in England in 2023. The authors examined the relationship between a practice’s staffing and financial inputs, and their outputs in terms of clinical quality, patient experience, and service volume. They concluded that “smaller practices were more efficient” and warned that “policies that encourage practice mergers may not deliver the efficiency gains expected.” These results echoed those of an earlier study from the same institution.

Three days later, a second paper was published by Tianchang Zhao and colleagues from the University of Manchester that appeared to reach a very different conclusion. This sophisticated econometric analysis explored the relationship between staffing levels and appointment volumes in more than 6,000 practices in England between mid-2022 and mid-2024. In particular, the authors estimate the number of additional appointments that would be generated by an extra member of staff of various types: qualified GP, GP trainee, nurse, other clinical staff and administrative staff. They also examined how these marginal effects varied by practice size and concluded that 

“national policy encouraging primary care practices to operate at scale offers a promising opportunity to increase the availability of appointments, as additional clinical staff at larger primary care organizations provide more additional appointments than those at smaller ones”.

So how might a rational policy-maker react to these two papers? The close alignment of the study population and study period leave little room for artefactual explanations for the apparently contradictory findings, although the two papers define practice size different ways. But in the meantime, should policy-makers choose between the two studies, or might there be a way to accept the headline conclusions of both, and seek to reconcile them?

One possible route to a synthesis, starts with noting the difference between the outputs measured in the two studies. Zhao is specifically focused on appointment volumes as an output measure. If increasing appointment volumes is our sole objective, then bigger practices might be the way to go, but this would seem to ignore the many other things that patients want from GP practices. As Zhao acknowledges, 

“determining the optimal practice size requires a balanced consideration of appointment availability, patient satisfaction with various aspects of primary care services, and the trade-offs between different clinical outcomes”. 

Onwunduba takes this broader view of practice outputs, incorporating measures of clinical quality and patient experience. Together, perhaps the two papers suggest that larger practices produce more appointments for a given level of input, but at a lower level of quality and with lower levels of patient satisfaction. In other words, larger practices are better at delivering more activity, but smaller practices deliver the right activity. 

Might care continuity, the extent to which a patient sees the same GP over time, be the mechanism that explains this effect? The evidence that care continuity is associated with better patient outcomes is almost overwhelming. More recently, care continuity was shown to increase the interval between patient consultations, such that practices that deliver higher levels of care continuity, need to make fewer appointments available to their patients. But levels of care continuity tend to be better in smaller practices. If this is the case, then it would support the growing call to refocus primary care policy on improving care continuity, instead of access. 

The papers raise a wider question about the ways in which healthcare efficiency is conceived. Efficiency measures a system’s outputs relative to its inputs. The key issue is how broadly outputs are defined. Are a system’s outputs limited to the activities it carries out, or should they also take account of service quality, patient experience, and outcomes? Defining outputs broadly may seem attractive, but it requires more data, more complex methods, and leads more often, to tentative, or qualified conclusions. The Health Foundation’s Productivity Commission, which is due to report over the coming months, is bravely adopting the broadest possible conception of productivity. Taking this perspective might help unblock some of the issues that have been dogging the NHS for many years, and refocus healthcare policy on what really matters.