How reliable are interviews and surveys as a measure of credibility?

Interviews or surveys are just but one possible source to assess the credibility, thus functionality, of institutions. It is why credibility theory advocates “multi-angulation” (figure below), the coupling of various qualitative and quantitative, as well as socio-economic, political, legal, historical and cultural sources.

Equally important is the way in which the research (be it founded on archival study, agent-based modeling, participatory observation, interviews or surveys) is structured around the variables, which one aims to measure. In this context, the FAT Framework and Conflict Analysis play a critical role.

Multi-angulation (more info)