Impact of local public goods on agricultural productivity growth in the U.S.

In this paper we revisit the issue on the impact of public R&D expenditure on US agricultural productivity growth. We estimate a dual cost function using a state-by-year panel data set. We construct the potential R&D “spillins” based on both geographical location and production mix. We also examine the role of the extension service, transportation network, and human capital in the process of technology dissemination. The results indicate that higher levels of local public goods, R&D spillins, extension activities, and an intensive transportation network decrease costs. The contributions to agricultural productivity from all series of R&D spillins are positive even though the social rate of return may differ.