How to combine and analyze all the data from diverse sources: a multilevel analysis of institutional trust in the world

Scholars who want to perform cross-national comparative research rely on data provided by International survey projects, which study the same concepts in varying countries and periods using different question wordings and scales. In this article, we propose a process to combine and analyse the data pertaining to the same concept—institutional trust—when measures and sources differ. We show how we combined 1327 surveys conducted from 1995 to 2017 by 17 survey projects in 142 countries. The database comprises close to 2 M respondents and 21 M answers to trust questions. We use local regression to visualize the trends in trust for different institutions and sources of data in different parts of the world. We complete these analyses with a 4-level longitudinal analysis of repeated measures. These analyses lead to reliably conclude that institutional trust is a property of the institutions themselves and of the context in which they operate since there is much more variance within respondents than between respondents and more variance between countries than over time. This research contributes to the current debates in political trust research. Since the process presented here can be applied to other fields of research, the research also contributes to enhance the possibilities for comparative cross-national analysis.