<p>This thesis was successfully defended on January 15, 2014 at McMaster University.</p> / <p>Understanding why policies change is an important pursuit for researchers and policy-makers alike. Research evidence is one of many possible factors that encourage or constrain policy change, as is the role of ‘networks’ of policy actors. Despite extensive empirical literature on each of evidence-informed health policy and policy networks, the two have rarely been studied together, particularly in low-income country policy environments. This thesis explores both of these variables in a broader structural context of institutions, interests and ideas. Concepts and approaches from social network analysis are applied to three distinct research questions and chapters with the objective to: 1) develop and test a conceptual framework for the integration of networks, institutions, interests and ideas as major variables explaining policy change; 2) test the relationship between policy network structure (closure and heterogeneity) on the use of research evidence and innovation across the three cases; and 3) model the factors that influence the formation of an evidence exchange relationship between policy actors, and the effect of those exchanges on actor-level use of research evidence. Taken together, the findings of this dissertation present persuasive support for adopting a network lens to study evidence-informed health policy and policy change.</p> / Doctor of Philosophy (PhD)