In Phase 3 of the ETPF research projects, we are aiming to build towards a longer term programme, which should provide a mix of research projects on different themes and of different styles. In Phase 3 and subsequently, some papers would certainly need to cover policy questions, which come under the heading "International Tax Design". One advantage of including such projects is that it enables us to bring to the ETPF first-rate economic theorists, who do not generally undertake empirical work, but who nevertheless are able to produce clear analysis of policy questions. But in phase 3 and subsequently, we also aim to include empirical projects relevant to determining international tax policy. These would include elements from the Phase 1 and Phase 2 themes: how taxes affect business decisions, and how taxes and business decisions affect welfare.