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| Gollin, Douglas. |
| This study asks whether the diffusion of modern varieties has affected the yield stability of wheat and maize production in developing countries between 1960 and 2004. The data suggest strongly that, over the past forty-plus years, there has been a striking decline in the relative variability of grain yields in wheat and (to a lesser extent) maize. The declines are strongest when measured as the standard deviation of yield divided by the mean, but there have also been declines in other measures of variability, such as the percentage deviation from trend. Declines in yield variability do not appear to be driven by increases in intensification (e.g., irrigation), nor do they appear to extend to crops, such as oilseeds, in which there has been little... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Crop Production/Industries. |
| Ano: 2006 |
URL: http://purl.umn.edu/25239 |
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| Gollin, Douglas; Smale, Melinda; Skovmand, Bent. |
| This paper develops a theoretical model for analyzing gene bank management decisions regarding the search for traits of economic value in ex situ collections of wheat. The model is applied to data on the probability of finding useful sources of resistance to Russian wheat aphid (Diuraphis noxia) and septoria tritici leaf blotch, using Monte Carlo simulations for sampling distributions, simulations of varietal diffusion paths, and actual cost data from searches. Three specific questions are posed and answered: (1) what is the optimal size of search among genetic resources of a given type for a trait of economic value? (2) what is the value of specialized knowledge about which genetic resources are most likely to display resistance? and (3) how should search... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Crop Production/Industries. |
| Ano: 1998 |
URL: http://purl.umn.edu/7695 |
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| Gollin, Douglas; Parente, Stephen L.; Rogerson, Richard. |
| Agriculture's share of economic activity is known to vary inversely with a country's level of development. This paper examines whether extensions of the neoclassical growth model can account for some important sectoral patterns observed in a current cross-section of countries and in the time series data for currently rich countries. We find that a straightforward agricultural extension of the neoclassical growth model restricted to match U.S. observations fails to account for important aspects of the cross-country data. We then introduce a version of the growth model with home production, and we show that this model performs much better. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Agribusiness; Productivity Analysis. |
| Ano: 2000 |
URL: http://purl.umn.edu/21797 |
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| Gollin, Douglas. |
| Many developing countries pursue policies that treat large and small firms differently. For example, large firms may be subject to a value added tax while small firms are explicitly exempted. Moreover, governments often find it impractical to collect taxes from the smallest enterprises; this may increase the tax burden for larger firms, whose compliance can be enforced. Such policies clearly affect the size distribution of firms. But how great is the impact on macro variables? How large are the resulting inefficiencies? And what are the dynamic effects on capital accumulation and economic growth? This paper uses a dynamic general equilibrium variant of the Lucas (1978) span-of-control model to address such questions. The model is matched to data from the... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Public Economics. |
| Ano: 1995 |
URL: http://purl.umn.edu/7488 |
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