Salway et al. BMC Public Health 2011, 11:514 http://www.biomedcentral.com/1471-2458/11/514 and health can have downsides, including: a tendency to reify concepts and essentialise migrant/minority ‘groups’ in an effort to harmonize across countries; a danger that analyses are superficial, being restricted to independent country descriptions rather than generating integrated insights; difficulties of balancing the need for meaningful findings at country level and more holistic products; and increased logistical complexity and costs. The present paper has not sought to advocate one particular approach. Indeed, many questions remain unanswered in our own minds as to the most appropri- ate way to design and conduct such comparative work. Nevertheless, it is clear that to-date public health researchers have devoted more effort to justifying their research topics than to clearly articulating why and how they intend to adopt a comparative research design. We therefore offer here a number of principles that may help to enhance the usefulness of such research. Framing the research: purpose and intended products We suggest that researchers should: Carefully consider why they are adopting a cross- national comparative design, what particular type of comparative analysis is intended, and what can and can not be learned from the proposed research. Undertake cross-national comparative work where it offers significant additional analytical purchase, and not merely because of funding imperatives; and clearly articulate the analytical opportunities that would not be achieved through a single country design. Think carefully about how research questions are framed to ensure that research does not inadver- tently promote or reinforce essentialist or patholo- gising accounts of migrant/minority people. Clearly articulate the relationship between them- selves and the commissioners and other stakeholders in the research and how this may shape, and perhaps compromise, the research process. Country and team selection We suggest that researchers should: Select countries not out of convenience or in response to funding imperatives, but so as to ensure the research questions can be addressed adequately. Reflect on the degree of similarity or contrast that may be helpful. Page 11 of 13 Give thought to whether the nation-state is the most appropriate unit of analysis and whether the research design can usefully incorporate analyses and sub- and supra-national level. Reflect carefully on their own ideological and epis- temological position in relation to researching migrant/minority health and the degree of compat- ibility with other members of the proposed interna- tional research team. Conceptualising and operationalising migrant/minority ‘groups’ We suggest that researchers should: Give adequate attention to understanding the socio- cultural, economic and political contexts in which migrant/minority people’s health experiences and outcomes are situated across the countries of focus. Carefully consider the utility and limitations of proposed approaches to conceptualising and opera- tionalising migrant/minority identities and ‘groups’. In particular, consider whether the adoption of fixed, statutory categories may reinforce hierarchical power. Carefully consider the pros and cons of creating harmonized datasets and of drawing direct compari- sons between similarly labelled ‘groups’ in different countries. Recent reviews of cross-national comparative research have commonly concluded that the understanding gained is often disappointing given the resources invested [15,20]. While such research offers great poten- tial to public health researchers who are keen to contri- bute to better health outcomes for migrant/minority populations, our experience suggests the need for much greater reflection on how such research should be designed and conducted. Preliminary studies of the type we undertook here would seem to be invaluable in order to assess the feasibility and likely contribution of proposed cross-national comparative work. Acknowledgements We thank all the service users, practitioners and researchers who participated in the country workshops and consultation exercises for their valuable insights and generosity of time. We also thank Heribert Kentenich, Kubilay Ertan and Heinz Rothgang for their support to the German wing of the study. We acknowledge the financial support of VolkswagenStiftung to this project. Author details 1Centre for Health and Social Care Research, Sheffield Hallam University, 32 Collegiate Crescent, Sheffield, S10 2BP, UK. 2Faculty of Nursing, University of Alberta, University Terrace, 8303-112 Street, Edmonton, T6G 2T4, Canada. 3Bernhard-Nocht-Institute for Tropical Medicine, Bernhard-Nocht-Str. 74,