GPonline has learned that NHS officials are citing evidence based on a disputed theory of optimum social group size derived from the size of primate clans in support of its plans for primary care collaborative hubs.
NHS England’s Next Steps for the Five Year Forward View report published last week revealed plans to incentivise every practice in England to join a primary care network (known last week as local care networks) covering 30,000 to 50,000 patients.
Director of primary care Dr Arvind Madan told GPonline the structures would be the ‘new delivery scaffolding’ for primary care, bringing together GPs with other doctors and health and care professionals to provide a single health and care system for localities.
The hubs will build on existing collaborations including MCPs, federations and primary care home models. Dr Madan said the 30,000 to 50,000 size, also used by the National Association of Primary Care (NAPC)’s primary care home model and cited by primary care minister David Mowat, ‘feels like a natural community, people have gravitated towards’.
When asked by GPonline what evidence there was to support primary care models of this size, NHS England officials cited sources that had informed projects and test sites, including a book by anthropologist and evolutionary psychologist Professor Robin Dunbar, called How Many Friends Does One Person Need? Officials said the theory indicated the best size for an integrated workforce was between 100 and 150, which translates into the 30,000- to 50,000-patient network size for primary care.
This theory is understood to have influenced the NAPC’s primary care home model, which in turn informed plans for primary care networks.
NAPC chair Dr Nav Chana told GPonline last week that its model was based on evidence that its size allowed for an integrated workforce, which did not risk relationships in the way a larger model might.
NHS England’s plans have also used evidence from Tower Hamlets, East London, where it says locality working at this size has seen improved targets and outcomes in areas such as COPD and type 2 diabetes. Officials have also suggested that benefits can come from economies of scale under this model while allowing primary care staff to maintain necessary relationships and knowledge of their local population.
Primary care minster David Mowat told MPs last month: 'We are finding that things are working better with GP practices being put into hubs of 35,000 to 40,000 people'. Asked by GPonline to provide evidence to support the minister's assertion, the DH said simply that evidence was emerging from primary care home pilots.
GPC deputy chair Dr Richard Vautrey cautioned against using Dunbar’s theory to determine a one-size-fits-all approach to GP networks. ‘'The Dunbar number is about the maximum functional size of social networks, but it's hard to extrapolate this to NHS local networks which have very many other complicating factors,' he said. ‘We should be careful therefore to avoid using this to assume there is a one-size-fits-all way of working for general practice and community services.’
In his book Professor Dunbar extrapolates from the size of primate groups to the optimum size of humans’ natural cognitive communities based on the relative size of the neocortex, which he claims is correlated to social group relations. The limit on the number of relationships a human can have, he says, is therefore 150 - Dunbar’s number. The book goes on to cite business practices where, it claims, a ‘rule of thumb’ is that 150 is a maximum workforce size to allow people to work well on a person-to-person basis without formal hierarchy.
Critics have pointed to other correlations with neocortex size such as territory size and diet, pointing out that human groups of other sizes have existed, and have called Dunbar’s theory simplistic.
Dr Vautrey added: ‘While we support practices working together with others within their area, and this can lead to greater resilience and support wider service developments, what makes sense for a city practice may well not be appropriate in a market town or rural area.
‘A large group operating over a large number of sites will work in a different way from much bigger practices working in one or two different sites. Equally it's just as important to take into account the relationships between those who could or should work alongside practices, such as community nurses and other healthcare staff. There is a risk that policy developed in London is assumed to be right for the rest of the country and that is not always the case.’
Last week the NAPC published its first impact assessment of three of its 92 primary care home sites which suggested reductions in emergency attendance and reduced GP appointment waiting times, as well as improved staff job satisfaction. NAPC chair Dr Nav Chana told GPonline the size of its model came from what works best. ‘There is some rationale and evidence to the number,' he said, because it allows for a workforce size which does not put at risk the important relationships of support which can be lost in bigger units.