Influence of provider mix and regulation on primary care services supplied to US patients.

Access to medical care and how it differs for various patients remain key policy issues. While existing work has examined clinic structure's influence on productivity, less research has explored the link between provider mix and access for different patient types - which also correspond to different service prices. We exploit experimental data from a large field study spanning 10 US states where trained audit callers were randomly assigned an insurance status and then contacted primary care physician practices seeking new patient appointments. We find clinics with more non-physician clinicians are associated with better access for Medicaid patients and lower prices for office visits; however, these relationships are only found in states granting full practice autonomy to these providers. Substituting more non-physician labor in primary care settings may facilitate greater appointment availability for Medicaid patients, but this likely rests on a favorable policy environment. Relaxing regulations for non-physicians may be an important initiative as US health reforms continue and also relevant to other countries coping with greater demands for medical care and related financial strain.