In the context of flourishing cross-national and multi-level research, the variety of macro and micro data sources available to researchers have evolved into an interdependent ecosystem of social indicators. Focusing on four comparative social surveys, this paper examines the extent to which secondary data users take advantage of a range of complementary data sources to broaden the breadth or strengthen the robustness of their research. Using two Google Scholar-based datasets of 2789 and 796 publications, we find that, despite the complex equivalence issues in comparative survey research, users combine data to a considerable extent, aiming to increase conceptual, geographic, and temporal coverage and cross-validate findings. Selecting the example of the European Social Survey, 183 journal articles are qualitatively examined to identify specific epistemic gains attained by analysts when combining ESS survey data with data from other comparative programmes. The strategy involves risks, emanating from either analysts' own misjudgements or arising from the wider issues of comparability and transparency in cross-national survey research. However, a number of data harmonisation platforms have recently emerged that may facilitate the standardisation of measures across surveys, augmenting the possibilities for future theory development and research.