Prioritisation research is activity aimed at working out which causes, interventions, organisations, policies, etc. do the most to make the world a better place. Organisations and projects within this cause include some policy think-tanks and some parts of economics. Within prioritisation research, we think the most high-priority area is long-run-focused cause-prioritisation. That is, research aimed at working out which causes do the most to make the world a better place in the long-run if we add more resources to them. Note that this research need not consist of detailed economic modelling. Cause-prioritisation can also involve down-to-earth projects like investigating room for more funding or aggregating expert opinion.