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.