Objective: This paper contributes to the debate on how process affects reliability of scientific evidence in health care. It discusses the use of different types of study designs in medicine and biology versus social sciences to raise scientific international evidence. Methods: A comparison of study designs used in clinical research (RCT and bridges studies (e.g. Hsiao CF et als,2007)) and in social sciences. Examples from clinical sciences are on environmental medicine and bridging studies. Examples from social sciences are presented on two characteristics of six European hypertensive patient surveys on cost of medicines (ENDEP-Lux, 2000): exemption criteria and classification of medicines for reimbursement. Results: The comparison of case studies shows similar problems for both clinical and financing study designs: imbalance of sample sizes between new and original sites for clinical bridges studies, and between national sampled patients with different access to health benefits for financing studies; the comparison also shows common recent development of bayesian decision models and choices of appropriate weighting of prior information (e.g. use of mixture prior information for judging similarity by the "positive treatment effect" in clinical research or use of different weighting between individual and population level for the financing studies). Moreover, selection of appropriate weighting in both types of studies face regulators and financing agencies that need to have confidence in the transferability of their results between regions. Conclusions: New developments of statistical analysis especially Bayesian evaluation both in global clinical research and social sciences can lead to a better integration of types of research designs. They can improve scientific evidence for health care policy decision processes. Context free research is not sufficient to integrate the effect of environmental modifiers (like in asthma) or variations in social and political processes (e.g. variation in exemption criteria especially during health reforms or systems in transition).