Salway et al. BMC Public Health 2011, 11:514 http://www.biomedcentral.com/1471-2458/11/514 meanings in use across the three countries. Instead, our objective here was to highlight how our cross-national comparative work vividly illustrated the way in which the concepts and terms relating to migrant/minority populations are neither natural nor neutral entities, but rather are the product and producer of particular forms of social relations. These observations highlighted the importance of: (i) clearly articulating our understandings of the key terms to be used in the research in ways that acknowledged their socio-historical foundations; and (ii) carefully considering the utility and limits of any ethnic or migrant categories employed - aspects that would not ordinarily come under scrutiny in single country work. In addition, a more challenging issue was raised - Is it possible or desirable to develop a set of concepts, terms and categories that are relevant across all three coun- tries? This is a contentious issue. While some research- ers advocate working towards standardized instruments and categories for use across diverse settings [13,15], others argue that processes of ‘ethnogenesis’ are so his- torically and geographically specific that such harmoni- zation is impossible and unwise [14]. This tension relates to the fundamental epistemological question of how comparative research should steer a course between identifying the similarities across, and the differences between, the settings under investigation [20,21]. Our preference was to follow the lead of researchers who have tried to adopt frameworks that encompass both national-level contextual specificity and universal pat- terns or trends [16,22]. We therefore adopted an approach that did not seek to impose standard concepts or measures (something we felt was neither conceptually nor operationally feasible) but rather to work with the national peculiarities of our three countries. This meant that our theoretical approach incorporated explicit attention to understanding processes of identification and categorisation rather than working with fixed cate- gories as taken-for-granted. At the same time, however, this approach did not preclude from our framework the consideration of over-arching processes that shape the maternity experiences and outcomes of migrant/minor- ity women across the three settings. Such an approach seems particularly appropriate to research on migration, ethnicity and health for at least two reasons. First, there is a danger that the adoption of standardized terminol- ogy and simplistic comparisons of fixed migrant/minor- ity categories risks the reification of concepts and essentialisation (whether in genetic or culturalist terms) of migrant/minority populations. Second, this area of work, perhaps more than any, demands that our theore- tical frameworks reflect the ‘social realities of the post- modern world’ [14, p58]; realities in which international migration, ethnic diasporas and transnational identities are juxtaposed with the contextual specificities of Page 5 of 13 particular settings. Our approach therefore sought to work both with and against the established discourses in the three countries to understand the social locations of migrant/minority groups and the implications for mater- nal health. Such an approach, we felt, offered the poten- tial for important new insights. At the same time, it was recognized that moving beyond accepted concepts and terms may create problems at a country-level. We were conscious of the need to engage with local stakeholders and to generate research products that were meaningful and applicable to these actors; suggesting the impor- tance of employing familiar concepts and terminology. Even the phrase ‘migrant/minority women’, which we adopted within the project as a shorthand for women who trace a significant part of their family heritage out- side their country of residence, would require explana- tion at the country level. Clearly, the more creative and flexible approach, while potentially fruitful, would undoubtedly necessitate additional effort. We also recognise that our proposed approach is by no means the norm in health focused research. Indeed, there are a growing number of quantitative ‘variable’ analyses that compare the health experiences and out- comes of groups of people similarly labelled and cate- gorised across countries [23-26]. While careful attention to the comparability of the outcome measures across national settings is a hallmark of these studies, we sug- gest that such work would benefit from similar scrutiny of the utility and meaning of the migrant/minority cate- gories employed, particularly if the ambition is to move beyond simple description, to explanation of differences and/or prescriptions for policy and practice. Understanding migrant/minority healthcare experiences and outcomes in wider socio-political context The diversity of concepts and labels in use highlighted above indicated a need for the whole research team to have an appreciation of the historical and present-day patterns of immigration and the policy and societal dis- courses relating to migration and ethnicity across the three countries. Our preliminary work therefore included the preparation of briefing papers that described these aspects for each country and allowed comparison across the settings. The key issues identified across the three countries showed both similarities and divergence, as summarised below in Table 1: In addition to identifying areas of divergence and commonality that would provide the backdrop for our subsequent investigations, the process of looking across the three national contexts served to highlight a number of more fundamental themes that deserved a greater focus within the conceptual framework for our study. First, multiple strands of policy and legislation were seen to have relevance to the ways in which migrant/