This volumeexamines current agricultural R&D policy, evaluating it in the context of the 100-plus-year history of U.S. public-sector agricultural R&D institutions and expenditures.

This is a prepublication version of J.M. Beddow, T.M. Hurley, P.G. Pardey, and J.M. Alston’s “Food Security: Yield Gap” chapter in N. Van Alfen, editor-in-chief, Encyclopedia of Agriculture and Food Systems, Vol. 3, San Diego: Elsevier, 2014, pp. 352-365.

Some studies have reported a slowdown in U.S. farm productivity growth, but the prevalent view among economists is to reject or downplay the slowdown hypothesis, implying that the rates of productivity growth experienced over the past half century can be projected forward. We set out to resolve...

Annual data for forty-eight states are used to account for changes in the composition of input and output aggregates over space and time, and thereby to obtain new evidence on changes in inputs, outputs, and productivity in U.S. agriculture. The measures change significantly when we use...

Reported rates of return to agricultural R&D are generally high, but they are likely to be biased, particularly because of attribution problems-mismatching research benefits with costs. The importance of attribution biases is illustrated here with new evidence for Brazil. During 1981-2003,...

Replaced with revised version of paper 08/14/07.

In general, reported rates of return to agricultural R&D are high, but questions have been raised about upward biases in the evidence. Among the reasons for this bias, insufficient attention to attribution aspects-matching of research benefits and costs-is a pervasive problem, the magnitude of...

Replaced with revised version of paper 07/10/09.