Unraveling PBF effects beyond impact evaluation: results from a qualitative study in Cameroon.

Introduction: Performance-based financing (PBF) has acquired increased prominence as a means of reforming health system purchasing structures in low-income and middle-income countries. A number of impact evaluations have noted that PBF often produces mixed and heterogeneous effects. Still, little systematic effort has been channelled towards understanding what causes such heterogeneity, including looking more closely at implementation processes.