The U.S. government has a long history of supporting private sector researc
h and development (R & D). The economic justification for government R & D
support is clear. Primarily because of knowledge spillovers, profit-maximiz
ing firms invest less than the socially optimal level of R & D. This market
failure creates the possibility that government can help mitigate the unde
rinvestment problem Public-private technology partnerships are the newest a
pproach to funding R & D. Technology partnerships include public funding of
industry-led R & D projects and private research consortia, and collaborat
ions between industry and government scientists. These programs hope to gen
erate research that yields commercial products and innovations. This articl
e discusses the rise of these programs, she theory supporting them the type
s of research projects they must fund to he successful, the technical and p
olitical obstacles they face in funding these projects, and the evaluations
of the largest partnership programs. This article concludes with policy re
commendations, recognizing that these programs have potential hut must over
come significant hurdles