This rapid evidence assessment examines and synthesises the evidence base on the development impact of DFI investment. The objective is to strengthen DFID’s understanding of the critical assumptions underpinning its private sector development (PSD) theory of change to inform future PSD programming decisions. In particular, this rapid evidence assessment looks at what the current evidence tells us about DFI investment impacts on: incomes access to goods and services; distributional impacts (specifically poverty, gender, youth and quality jobs).