Determinants of effectiveness of a novel community health workers programme in improving maternal and child health in Nigeria Improved mother and child health (MCH) continues to be an issue of international priority, particularly for sub-Saharan African countries. Evidence suggests that schemes involving Community Health Worker (CHWs) can be effective in improving the health of mothers and children. Although such schemes are implemented in some developing countries such as Bangladesh, to guide further developments, much better understanding is needed on what makes CHW programmes successful and under what circumstances.   In Nigeria, despite significant improvements, mother and child health remains an issue of concern, particularly in rural areas where most vulnerable groups live. In 2012, the Federal Government of Nigeria established the Subsidy Reinvestment and Empowerment Programme (SURE-P) to invest the revenue from fuel subsidy reduction into a social security programme to improve lives of most vulnerable populations.   One SURE-P component, implemented in selected facilities in each State, focuses on maternal and child health (SURE-P/MCH). The idea is that recruitment of CHWs, combined with infrastructure development, and improved availability of supplies and medicines, will improve access to quality health services, and ultimately, improve mother and child health. Since December 2012, Conditional Cash Transfers (CCT) have also been added at selected sites ('SURE-P/MCH+CCT'). These incentive payments to pregnant mothers are linked to use of health services at different stages: e.g. for antenatal care visits and facility deliveries.   The AIM of this project is to inform strengthening and scaling up of community health worker (CHW) programmes. This will be achieved by investigating two implementations (i.e. with and without conditional cash transfers) of a Nigerian CHW programme, to understand what factors, under what conditions, promote equitable access to quality services, and improve maternal and child health outcomes. We will do so by: 1.Developing an in-depth understanding of the context and the process of implementation of the interventions, including relations between health workforce and infrastructure and supplies; 2.Identifying, assessing and comparing the intervention outputs (e.g. skills and practices of CHWs and efficiency of primary health care facilities) and outcomes (e.g. equitable access to quality MCH services and attainment of MCH outcome targets); 3.Developing an empirically-based and theoretically-grounded model of complex relations between the people involved, context, implementation process, outputs and outcomes of the interventions; 4.Developing transferable best practices for scalability (expansion within a broadly similar context) and generalizability (expansion to different contexts) of the interventions.  This five-year research and development project will be implemented in two States in Nigeria - Niger State in the North and Anambra State in the South, which were selected in consultation with the Federal MOH and SURE-P national programme officer. Selecting two states from different parts of the country will provide an opportunity for different contextual factors that affect the implementation and outcome from the programme to be better elucidated and ensure that the findings are generalisable to the entire country. Within each State we will select three Local Government Areas (LGAs) clusters: one with SURE-P/MCH, one with SURE-P/MCH+CCT and one with no intervention. In each State the two interventions will be assessed against each other and against the comparison (i.e. no implementation) site.   We will work closely with local, State and Federal policymakers and practitioners, to generate answers that can be used to inform their policy decisions. We expect that better understanding of performance of the CHW programme in Nigeria will inform further strengthening of the existing programme, its replication within Nigeria, and other similar countries considering the implementation of CHW initiatives. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.