Salway et al. BMC Public Health 2011, 11:514 http://www.biomedcentral.com/1471-2458/11/514 national nature of our study again created challenges as well as opportunities. Identifying meaningful research questions There were significant differences across our three countries in terms of both the volume of existing research in the field of migrant/minority maternal health and the prevailing policy and practice context of mater- nity services. This presented challenges in terms of iden- tifying a set of research questions which, if answered, would be meaningful for each of the country contexts, as well as provide opportunities for broader comparative analysis. We were aware of past criticisms that much comparative research fails to go beyond descriptive accounts of the individual countries included to produce deeper interpretations and genuine integration of scho- larship [15,17,20]. In addition, however, we were con- cerned that our findings should be pertinent to national policy-makers and practitioners, lending themselves to translational activities, rather than being of purely theo- retical or academic interest. Our cross-country preliminary work identified com- mon issues facing migrant/minority women and mater- nity services across the three countries despite their divergence in social, policy and service constellation, including, among others: ineffective cross-language and cross-cultural communication; discrimination, stereotyp- ing and insensitivity at provider and program levels; and a failure to recognize and respond to the complex issues within some migrant women’s lives (such as trauma, iso- lation, mobility, poverty). Such transcending issues were therefore taken as the starting point to develop a broad set of research questions that had general applicability. At the same time, however, the contrasting knowledge bases and service contexts demanded that we also gen- erate country-specific research questions to guide data generation and analysis. In addition, the review of existing evidence across the settings forced the research team to reflect on (i) the nature, source and implications of biases in the existing data sources and evidence base, and (ii) our responsibil- ities as researchers to consider not just the rigour of the present study, but our contribution to the wider evi- dence base and the extent to which it serves the needs of all sections of the population. Working with divergent data sources A further complicating factor was the significant differ- ences across our three countries in the availability and accessibility of data sources that might lend themselves to secondary analysis. For instance, while both the UK and Canada had recently conducted surveys of women’s maternity experiences which included samples (albeit relatively small) of migrant/minority women [60,61], no Page 8 of 13 such comparable German data were available. There were also important differences in terms of available administrative data on maternity service use with the UK having ethnicity data and the other countries only country of birth. Furthermore, while the UK and Canada had quite a large amount of qualitative evidence relating to maternal health experiences of migrant/minority women, this type of evidence was virtually non-existent in Germany. These divergent situations meant it was simply inappropriate to employ identical research designs in the three settings. Instead, we adopted a design that involved new qualitative data generation in Germany and meta-synthesis of existing qualitative evi- dence combined with secondary analysis of survey data in the UK and Canada. In contrast, some elements of our study were designed to be conducted more-or-less similarly across the three countries and this was more feasible where new data collection was warranted for all three countries, for instance an interpretive analysis of policy documents and key informant interviews with policy-makers. Clearly, then, the cross-national nature of our study added significant complexity to the methods of data generation we had to employ. Integrating data analysis and interpretation across the country settings The approach to research design described above meant that we could ensure the viability and relevance of ana- lyses in all three countries. It did, however, raise the issue of how to avoid the project developing into three parallel studies operating independently rather than an integrated whole yielding more than the sum of its parts. As discussed above, our conceptual work clearly indicated a comparative approach intended to generate insights that extended beyond the country-level contexts to more over-arching processes. The issue of how data should be integrated across divergent settings in cross- national work is widely acknowledged to be challenging [20,22], but there is little in the way of coherent gui- dance on how to go about this process in practice. As described above, we were faced with the possibility of generating data from highly divergent socio-political set- tings using different methodological tools. How then should we design and justify our comparative analytical method? Here it was helpful to consider how existing models of (i) integrating data in mixed methods studies, and (ii) approaches to cross-national comparison within social science, might inform our approach. In relation to mixed methods work, Mason’s [62] notion of ‘Con- structing multi-dimensional explanations’ is useful. In contrast to ‘triangulation’, where the aim of employing different methods is to achieve more accurate measure- ment and consequently a more valid representation of