This series provides the best papers from the Annual World Bank Conference on Development Economics, a forum begun in 1989 for discussion and debate of important policy issues facing developing countries. The conferences emphasize the contribution that empirical economic research can make to understanding development processes and to formulating sound development policies. Conference papers are written by researchers in and outside the World Bank. The review process, a mix of internal and external review, is overseen by an Advisory Committee for the series. This series is produced by the World Bank's Development Economics Vice Presidency.