 Joanne Weider was established in 1985 to help promote better living conditions for the poorest people in the world. Over the last decade, we have produced more than 2,000 studies on economic and social development. Here are some important lessons from this work. We find that aid does promote economic growth. We can't expect aid to solve all development problems. And we need to be patient. The gains from aid accumulate over the long term, decades, not years. In order to better understand whether successful interventions can be replicated or adapted elsewhere, we need to think about local context. A key lesson for development research is that three things matter. Data, data and data. Relationships and trust with the local governments are essential. Policy matters. In Latin America, the decline in equality has been driven by social protection and modest increases in progressive tax. Policymakers really want to act based on poverty results. But these results need to be coherent, comprehensive and credible. Commitment from the highest level of government is required to ensure coherence and accountability. Actions are taken to resolve constraints for private sector development. Third, experimentation and then finally the need for feedback from the private sector to government such that lessons can be learned for the future. The lesson for extractives is don't give up. Manager in ways that are politically and environmentally sustainable. No country can make a headway without having access to the right information and who knows better what policies we need than ourselves. It is indeed possible to strengthen capacity but only if you are in it for the long haul. Gender matters but it has to be studied along with other dimensions of one's identity. We have to have access to high quality level data from the revenue services. Bringing local knowledge together with the expertise of researchers who have worked in the field for many years in developed countries is at the heart of high quality research.