Conference Paper"While the role of formal and informal institutions has been long recognized among common-pool resources scholars working under the Institutional Analysis and Development Framework (IAD), not much attention has been devoted to disentangling the relative influence of each one on social behavior. We explore this issue through the application of the grammar of institutions, semi-structured interviews, and Q-sort methods. The goal of this paper is two-fold. First, the paper seeks to provide a deeper understanding of the interplay between formal and informal institutions on policy compliance. We do so in the context of aquaculture policies in the State of Colorado, USA. Second, this paper seeks to continue to develop Crawford and Ostrom’s grammar of institutions as an analytical tool for systematic institutional analysis. The results from the case study are mixed. We found some respondents reporting strong alignment between informal and the formal institutions but others reporting weak alignment. Additionally, feelings of personal guilt or shame and fear of social disapproval, together, were cited as being more influential in shaping individuals’ decision making regarding compliance with formal institutions than was fear of monetary sanctioning. The paper concludes with a discussion of the unexpected relationships among different syntactic elements of the grammar thereby deepening the understanding of how the grammar of institutions can help in the examination of policy documents and explain human behavior.