Yield improvements are critical to ensuring food security for a growing world population especially in view of the increasing potential for use of land in biofuel production. Efforts to sustain the impressive rate of past productivity gains, epitomized by such successes as the Green Revolution, are bound to rely on biotechnology innovations such as those responsible for the development of genetically engineered (GE) crops. Some argue that the use of biotechnology can substantially improve yields relative to the trajectory established by traditional breeding in the 20th century. Because U.S. adoption of GE varieties has been very strong since their introduction in the late 1990s, we investigated empirically whether and to what extent the GE technology has improved realized yields. We study this question for nonirrigated U.S. maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] yields over 1964 through 2010, having controlled for local effects, weather, fertilization, and the preexisting (non‐GE) crop improvement trend. For maize we find that GE varieties have increased realized yields, with a stronger gain in the Central Corn Belt (CCB). For soybeans, GE varieties appear to have slightly reduced yields. For both crops we find a strong trend in yield growth, which may have accelerated in recent years within the CCB. However, the combined effects of yield trend and GE adoption are predicted to fall short of the growth rate envisioned by industry projections.

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We analyze dynamic private provision of a discrete public good by heterogeneous agents, who differ in terms of their levels of impatience, in a differential game framework. In contrast to the strategic complementarity result for homogeneous individuals, we show that an asymmetric completion Markov perfect equilibrium exists, where the individual contributions and the strategic behaviors depend crucially on an impatience differential: the difference in rates of time preference across groups of individuals. When this differential is insignificant, contributions of both types of individuals are strategic complements. On the other hand, when this impatience differential exceeds a threshold, the contributions of impatient individuals become strategic substitutes, whereas the contributions of patient individuals remain strategic complements. We show that group size has an interesting role to play in the strategic behavior: increasing the number of patient individuals aggravates the incentives to free‐ride by the impatient agents. We also derive a condition under which all the socially beneficial projects get completed in the equilibrium.

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We estimate a travel cost model for the George Washington & Jefferson National Forests using an On-Site Latent Class Poisson Model. We show that the constraints of ad-hoc truncation and homogenous preferences significantly impact consumer surplus estimates derived from the on-site travel cost model. By relaxing the constraints, we show that more than one class of visitors with unique preferences exists in the population. The resulting demand functions, price responsive behaviors, and consumer surplus estimates reflect differences across these classes of visitors. With heterogeneous preferences, a group of ‘local residents’ exists with a probability of 8% and, on average take 113 visits.