Karin Diaconu, Jennifer Falconer, Adrian Verbel, Atle Fretheim, Sophie Witter

There is growing interest in paying for performance (P4P) as a means to align the incentives of healthcare providers with public health goals. Rigorous evidence on the effectiveness of these strategies in improving health care and health in low- and middle-income countries (LMICs) is lacking; this is an update of the 2012 review on this topic. To assess the effects of paying for performance on the provision of health care and health outcomes in low- and middle-income countries. We searched CENTRAL, MEDLINE, Embase, and 10 other databases between April and June 2018. We also searched two trial registries, websites, online resources of international agencies, organizations and universities, and contacted experts in the field. Studies identified from rerunning searches in 2020 are under 'Studies awaiting classification.' We included randomized or non-randomized trials, controlled before-after studies, or interrupted time series studies conducted in LMICs (as defined by the World Bank in 2018). P4P refers to the transfer of money or material goods conditional on taking a measurable action or achieving a predetermined performance target. To be included, a study had to report at least one of the following outcomes: patient health outcomes, changes in targeted measures of provider performance (such as the delivery of healthcare services), unintended effects, or changes in resource use. We extracted data as per original review protocol and narratively synthesised findings. We used standard methodological procedures expected by Cochrane. Given diversity and variability in intervention types, patient populations, analyses and outcome reporting, we deemed meta-analysis inappropriate. We noted the range of effects associated with P4P against each outcome of interest. Based on intervention descriptions provided in documents, we classified design schemes and explored variation in effect by scheme design. We included 59 studies: controlled before-after studies (19), non-randomized (16) or cluster randomized trials (14);  and interrupted time-series studies (9). One study included both an interrupted time series and a controlled before-after study. Studies focused on a wide range of P4P interventions, including target payments and payment for outputs as modified by quality (or quality and equity assessments). Only one study assessed results-based aid. Many schemes were funded by national governments (23 studies) with the World Bank funding most externally funded schemes (11 studies). Targeted services varied; however, most interventions focused on reproductive, maternal and child health indicators. Participants were predominantly located in public or in a mix of public, non-governmental and faith-based facilities (54 studies). P4P was assessed predominantly at health facility level, though districts and other levels were also involved. Most studies assessed the effects of P4P against a status quo control (49 studies); however, some studies assessed effects against comparator interventions (predominantly enhanced financing intended to match P4P funds (17 studies)). Four studies reported intervention effects against both comparator and status quo. Controlled before-after studies were at higher risk of bias than other study designs. However, some randomised trials were also downgraded due to risk of bias. The interrupted time-series studies provided insufficient information on other concurrent changes in the study context. P4P compared to a status quo control For health services that are specifically targeted, P4P may slightly improve health outcomes (low certainty evidence), but few studies assessed this. P4P may also improve service quality overall (low certainty evidence); and probably increases the availability of health workers, medicines and well-functioning infrastructure and equipment (moderate certainty evidence). P4P may have mixed effects on the delivery and use of services (low certainty evidence) and may have few or no distorting unintended effects on outcomes that were not targeted (low-certainty evidence), but few studies assessed these. For secondary outcomes, P4P may make little or no difference to provider absenteeism, motivation or satisfaction (low certainty evidence); but may improve patient satisfaction and acceptability (low certainty evidence); and may positively affect facility managerial autonomy (low certainty evidence). P4P probably makes little to no difference to management quality or facility governance (low certainty evidence). Impacts on equity were mixed (low certainty evidence). For health services that are untargeted, P4P probably improves some health outcomes (moderate certainty evidence); may improve the delivery, use and quality of some health services but may make little or no difference to others (low certainty evidence); and may have few or no distorting unintended effects (low certainty evidence). The effects of P4P on the availability of medicines and other resources are uncertain (very low certainty evidence). P4P compared to other strategies For health outcomes and services that are specifically targeted, P4P may make little or no difference to health outcomes (low certainty evidence), but few studies assessed this. P4P may improve service quality (low certainty evidence); and may have mixed effects on the delivery and use of health services and on the availability of equipment and medicines (low certainty evidence). For health outcomes and services that are untargeted, P4P may make little or no difference to health outcomes and to the delivery and use of health services (low certainty evidence). The effects of P4P on service quality, resource availability and unintended effects are uncertain (very low certainty evidence). Findings of subgroup analyses Results-based aid, and schemes using payment per output adjusted for service quality, appeared to yield the greatest positive effects on outcomes. However, only one study evaluated results-based aid, so the effects may be spurious. Overall, schemes adjusting both for quality of service and rewarding equitable delivery of services appeared to perform best in relation to service utilization outcomes. The evidence base on the impacts of P4P schemes has grown considerably, with study quality gradually increasing. P4P schemes may have mixed effects on outcomes of interest, and there is high heterogeneity in the types of schemes implemented and evaluations conducted. P4P is not a uniform intervention, but rather a range of approaches. Its effects depend on the interaction of several variables, including the design of the intervention (e.g., who receives payments ), the amount of additional funding,  ancillary components (such as technical support) and contextual factors (including organizational context).