Private Enterprise Development in Low Income Countries (PEDL) is a joint research initiative of CEPR and DFID. Over the period 2011-6 it will pursue a research agenda focusing on private-sector development. It starts from the need to develop a better understanding of what determines the strength of market forces driving efficiency in LICs. Existing research suggests that the private sector in these countries faces a multitude of constraints. These constraints interact with one another. For example, the strategic interaction of firms with market power will be affected by the regulatory regime governing both new entrants and incumbent firms. What is needed is research which allows us to understand how these constraints interact.