Transparency policies in public administration have gained traction in public debates and in the academic community due to the high expectations that they have generated both at a civic and institutional level. From a theoretical viewpoint, institutional change and institutional evolution have been widely studied and identified. However, despite the existence of contributions examining how endogenous and exogenous institutional factors affect transparency policies, the link between the latter and institutional dynamics of adaptation and change has not yet been significantly explored. In the case of Spain specifically, there isn’t enough evidence showing the impact of the Transparency Law on local governments. In this working paper, we will propose an attempt of merging transparency and institutional change in local governments. The purpose is to provide a tool for assessing the impact of the Transparency Law 19/2013 in Spanish local councils.