Patients in single-handed practices and those run by less than two whole-time equivalent GPs are happier overall and give higher ratings, particularly in terms of access to a named GP.
Almost 83 per cent of patients in small practices said they were happy with the service they got compared with less than 76 per cent of patients in group practices of four or more GPs.
The findings fly in the face of plans published last week by NHS London to develop a network of super-surgeries supplying 50,000 patients.
'In Northern Ireland overall satisfaction decreased as practice size increased,' lead author Dr Karen Galway wrote in the Irish Medical Journal.
'Access to any doctor was worst in the larger practices in Northern Ireland,' she added.
Small practices offered better access to a named doctor, with almost half of patients in small practices having same-day access to the doctor of their choice, compared with only 4 per cent of patients in large practices.
'Increasing practice size is associated with lower satisfaction generally and accessibility specifically,' the authors report.
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