Policy Spandrels: How Design Decisions Can Open Up Spaces for Unintended Policy Change

This article introduces the concept of policy spandrels to make sense of public policies producing second‐order effects that are unintentional from the perspective of policy design and yet are fraught with consequences. By analogy with architectural spandrels—leftover spaces that can be used for unforeseen purposes—policy change can be enabled by a new structure of opportunity emerging from prior decisions, in a way that was not intended by policymakers. In turn, this structure can provide other actors with means to achieve their policy goals. After engaging in concept formation and showing how the underlying model of decision‐making is aligned with the most prominent theories of the policy process, this article outlines a procedure for detecting policy spandrels empirically. Two illustrations on their roles are then offered. The concluding section discusses how the concept of policy spandrels confers additional analytical leverage to the study of policy change.