Recently there has been an increase in the number of empirical studies that investigate skilled, long-term international mobility, particularly the most common forms – international assignees/assigned expatriates (AEs), self-initiated expatriates (SIEs) and skilled (im)migrants (SMs). Two issues have become apparent: there appear to be problems with construct clarity; and the expatriate type appears to be linked to a specific research design. A sample of 296 empirical studies of AEs, SIEs and SMs published from 2005 to 2014, broadly within the field of human resource management, was coded to examine the research processes adopted: conceptualization, research design, data collection, and data analysis. Comparative analyses revealed problems in construct clarity for the expatriate types, with AEs and SMs less distinct constructs than SIEs. Systematic differences arose in the research paradigms employed: an exploratory inductive paradigm most often informed studies of SMs, while a more positivist paradigm informed studies of AEs. Research is needed to explain why researchers adopt different paradigms and whether their differences affect the results. Improvements are suggested for the research process and also to help end-users to access research results.