Our knowledge of how policy innovations diffuse in federal systems cou
ld be enhanced by paging greater attention to the behavior of policy e
ntrepreneurs. This study shows how policy entrepreneurs have helped st
imulate the diffusion of stale school-choice plans by collecting and g
enerating evidence of the workability of this innovation. Importantly,
these policy entrepreneurs have often used evidence from local experi
ments to promote state policy change. Thus, a state-focal nexus exists
in the diffusion of school choice. This analysis suggests that there
is value in conceptualizing policy innovation diffusion in a federal s
ystem as both a horizontal (that is, state to state) and a vertical (t
hat is, state and local) phenomenon.