What makes policy complex?

Previous research finds that policy complexity affects important political processes including legislative delegation and policy diffusion. However, policy complexity is not directly observable and the search for a reasonable proxy constitutes a major challenge for scholars. This research note presents a concise and measurable definition of complex policy based on two aspects: a policy's textual sophistication and its ties to other rules and regulations. Using crowdsourcing and a pairwise comparison framework it is shown that the proposed defining features are crucial for humans' understanding of policy text. The proposed definition is then operationalized using a large corpus of European Union rules and is shown to outperform alternative operationalizations of policy complexity in predicting the level of legislative delegation.