Quality of care is an issue for health systems worldwide. Overprovision, or healthcare for which the harms outweigh the benefits, is an aspect of quality often overlooked in low- and middle-income countries. As well as harming individual patients, overprovision represents a waste of resources and opportunity cost as countries work towards universal health coverage. Additionally, overprovision of antibiotics and antimalarials contributes to the development of antimicrobial resistance. There is particular concern that in the private sector, which is growing in many low- and middle-income countries, financial incentives may encourage providers to induce demand. I led the development of standardised patient cases of asthma, non-malarial febrile illness, tuberculosis and upper respiratory tract infection, that would allow overprovision to be studied. I used 909 standardised patient visits to measure overprovision in 227 private for-profit and not-for profit health facilities in Tanzania. I classified overprovision into three domains of harm: economic, public health and clinical. There was overprovision in 81.4% of visits, but no association between a facility being for-profit and overprovision (OR= 1.15, 95% CI: 0.66 – 2.03). In a randomised experiment, 86.0% of standardised patients who expressed knowledge that antibiotics were unnecessary received them, compared to 94.8% of those who did not (p=0.074). Providers who exerted more effort in the consultation, measured by history questions and physical exams, were more likely to provide correct care (RR=1.87, 95% CI: 1.47 – 2.38) and less likely to overprovide (RR=0.93, 95% CI: 0.88 – 0.98). My results suggest there is widespread overprovision in the Tanzanian private sector. In contrast with pre-study hypotheses, overprovision was not less common in not-for-profit facilities, and patients signalling knowledge of appropriate antibiotic use had no more than a modest effect on receiving them. In light of these findings, I discuss future avenues for research, policy implications and the range of reforms that could curb overprovision.
