The evidence review presents a systematic, multisectoral search of publications in the academic and grey literature. The search was restricted to quantitative studies published between 2000 and 2020 that assessed the effectiveness of one or more RBP interventions using experimental, quasiexperimental or non-causal designs. Based on sector-, intervention- and implementation-related characteristics extracted from a sample of 428 studies that met these inclusion/exclusion criteria, we developed an evidence gap map (EGM). The EGM followed a consistent intervention/outcome framework to highlight the distribution of the evidence base on the impacts of various RBP interventions on beneficiary-, service-provider- and investor/system-level outcomes.

The EGM reveals that vouchers, pay-for-performance models, payments for environmental services and conditional cash transfers have been extensively studied, whereas the evidence base on broader RBP modalities is much thinner. It highlights regional patterns in the use of these modalities: most evidence comes from North America, East Asia and Pacific, sub-Saharan Africa, and Latin America and the Caribbean. Evidence from South Asia and especially from the Middle East and North Africa was limited. Nearly half the evidence across all countries is drawn from applications in the health sector, followed by agriculture and forestry, and education; evidence on RBPs in the energy sector is sorely lacking.

Using the same intervention/outcome framework, we developed an intervention heat map (IHM) that highlights the distribution of 15 approved financial commitments by the Green Climate Fund (GCF) that employ results-based modalities. Nearly all this amount (representing approximately 7 per cent of the GCF’s total commitments between 2015 and 2020) was allocated as part of the GCF’s REDD+ pilot programme, which rewards countries for achieving verified emissions reductions from forestry programmes.

A comparison of the EGM and the IHM reveals that there is potential for greater use of resultsbased approaches in the GCF’s funding portfolio, including the use of vouchers and conditional cash transfers, which have already been deployed in GCF-supported projects. In addition, there is considerable potential to (i) broaden the GCF’s existing RBP-based commitments to projects to enhance beneficiaries’ adaptive capacity and to ensure long-term sustainability of project impacts, and (ii) increase support for projects that directly incentivize service providers.