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on Discrete Choice Models |
| By: | Seo, Sungno Niggol; Mendelsohn, Robert |
| Abstract: | This paper uses quantitative methods to examine the way African farmers have adapted livestock management to the range of climates found across the African continent. The authors use logit analysis to estimate whether farmers adopt livestock. They then use three econometric models to examine which species farmers choose: a primary choice multinomial logit, an optimal portfolio multinomial logit, and a demand system multivariate probit. Compar ing the results of the three methods of estimating species selection reveals that the three approaches yield similar results. Using data from over 9,000 African livestock farmers in 10 countries, the analysis finds that farmers are more likely to choose to have livestock as temperatures increase and as precipitation decreases. Across all methods of estimating choice, livestock farmers in warmer locations are less likely to choose beef cattle and chickens and more likely to choose goats and sheep. As precipitation increases, cattle and sheep decrease but goats and chickens increase. The authors simulate the way farmers ' choices might change with a set of uniform climate changes and a set of climate model scenarios. The uniform scenarios predict that warming and drying would increase livestock ownership but that increases in precipitation would decrease it. The climate scenarios predict a decrease in the probability of beef cattle and an increase in the probability of sheep and goats, and they predict that more heat-tolerant animals will dominate the future African landscape. |
| Keywords: | Livestock & Animal Husbandry,Wildlife Resources,Peri-Urban Communities,Rural Urban Linkages,Climate Change |
| Date: | 2007–07–01 |
| URL: | http://d.repec.org/n?u=RePEc:wbk:wbrwps:4277&r=dcm |
| By: | Seo, Sungno Niggol; Mendelsohn, Robert |
| Abstract: | This paper develops the structural Ricardian method, a new approach to modeling agricultural performance using cross-sectional evidence, and uses the method to study animal husbandry in Africa. The model is intended to estimate the structure beneath Ricardian results in order to understand how farmers change their behavior in response to climate. A survey of over 5,000 livestock farmers in 10 countries reveals that the selection of species, the net income per animal, and the number of animals are all highly dependent on climate. As climate warms, net income across all animals will fall, especially across beef cattle. The fall in net income causes African farmers to reduce the number of animals on their farms. The fall in relative revenues also causes them to shift away from beef cattle and toward sheep and goats. All farmers will lose income but the most vulnerable farms are large African farms that currently specialize in beef cattle. Small livestock and large livestock farms respond to climates differently. Small farms are diversified, relying on dairy cattle, goats, sheep, and chickens. Large farms specialize in dairy and beef cattle. Estimating a separate multinomial logit selection model for small and large farms reveals that the two types of farm choose species differently and specifically have different climate response functions. The regressions of the number of animals also reveal that large farms are more responsive to climate. The results indicate that warming will be harmful to commercial livestock owners, especially cattle owners. Owners of commercial livestock farms have few a lternatives either in crops or other animal species. In contrast, small livestock farms are better able to adapt to warming or precipitation increases by switching to heat tolerant animals or crops. Livestock operations will be a safety valve for small farmers if warming or drought causes their crops to fail. |
| Keywords: | Livestock & Animal Husbandry,Wildlife Resources,Rural Urban Linkages,Peri-Urban Communities,Dairies & Dairying |
| Date: | 2007–07–01 |
| URL: | http://d.repec.org/n?u=RePEc:wbk:wbrwps:4279&r=dcm |
| By: | Dagsvik John. K.; Locatelli Marilena (University of Turin); Strom Steinar (University of Turin) |
| Abstract: | This paper analyzes the properties of a particular sectoral labor supply model developed and estimated in Dagsvik and StrÃÂøm (2006). Agents have preferences over sectors and latent job attributes. Moreover, the model allows for a representation of the individual choice sets of feasible jobs in the economy. The properties of the model are explored by calculating elasticities and through simulations of the effects of particular tax reforms. The overall wage elasticities are rather small, but these small elasticities shadow for much stronger sectoral responses. An overall wage increase and, of course, a wage increase in the private sector only, gives women an incentive to shift their labor supply from the public to the private sector. Marginal tax rates were cut considerably in the 1992 tax reform. We find that the impact on overall labor supply is rather modest, but again these modest changes shadow for stronger sectoral changes. The tax reform stimulated the women to shift their labor from the public to the private sector and to work longer hours. A calculation of mean compensated variation shows that the richest households benefited far more from the 1992 tax reform than did the poorest households. |
| Date: | 2007–07 |
| URL: | http://d.repec.org/n?u=RePEc:uto:dipeco:200706&r=dcm |