International talent flow is critical to meeting the needs for skilled human capital in global and multinational organisations and in developed and developing countries. Recent decades have witnessed a boom in research into long-term skilled international mobility, especially the traditional category of international assignees, but also skilled immigrants and a relatively new expatriate type: self-initiated expatriates. The upsurge in empirical interest has highlighted a number of issues relating to the way the research has been conducted. This article examines methodological issues associated with research into the three expatriate types and seeks to advise researchers on how future research can be conducted to improve the robustness of results. In this way, practitioners and policy makers may be able to make more use of the empirical evidence.