Processes of privatisation and liberalisation around the world would lead us to expect a growth in the private provision of health and social care services, which in turn we would expect to lead to a growth in the international trading of such services. However, the available data are not adequate to allow us to develop a clear and comprehensive picture of the scope and nature of this emerging world market. What data do exist may take a variety of forms and be pitched at different levels of analysis. Such data may be focused at the level of firms providing such services, at the national level; at the level of regional organisations and agreements; or at the level of international organisations and agreements. This article discusses the methodological problems and challenges of attempting to integrate such diverse forms of data and levels of analysis. It is concluded that a comprehensive analysis must not only include all of these levels, but take account of the ways in which processes at different levels may interact to reinforce the tendency towards trade in healthcare services.