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| Registros recuperados: 22 | |
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| Zhuang, Yan; Dimitri, Carolyn; Jaenicke, Edward C.. |
| We use a two-stage, sample selection model to investigate organic milk purchases using Neilsen’s Homescan data. In the first stage, households decide on a weekly basis to buy mainly organic milk or non-organic milk. Results from this stage show that higher income, better education, having children at home, and several other demographic and marketing variables have a positive effect on organic choice. In the second stage, consumers then choose to buy mainly private label milk or national brand milk conditional on their first-stage choice. Most demographic and marketing variables are found to affect the organic and non-organic private label decision in the same way. However, our results show that a few factors, such as marriage status and children,... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Organic milk; Private label; Sample selection; Agribusiness; Consumer/Household Economics; Demand and Price Analysis. |
| Ano: 2009 |
URL: http://purl.umn.edu/49207 |
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| Key, Nigel D.; McBride, William D.. |
| Estimating how the use of production contracts affects farm productivity is difficult when unobservable factors are correlated with both the decision to contract and productivity. To account for potential selection bias, this study uses the local availability of production contracts as an instrument for whether a farm uses a contract in order to estimate the impact of contract use on total factor productivity. Results indicate that use of a production contract is associated with a large increase in productivity for feeder-to-finish hog farms in the United States. The instrumental variable method makes it credible to assert that the observed association is a causal relationship rather than simply a correlation. |
| Tipo: Journal Article |
Palavras-chave: Productivity; Production contracts; Instrumental variables; Sample selection; Productivity Analysis. |
| Ano: 2008 |
URL: http://purl.umn.edu/45659 |
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| McBride, William D.; Key, Nigel D.; Mathews, Kenneth H., Jr.. |
| Antimicrobial drugs are fed to hogs at sub-therapeutic levels to prevent disease and promote growth. However, there is concern that the presence of antimicrobial drugs in hog feed is a factor promoting the development of antimicrobial drug-resistant bacteria. This study describes the extent to which antibiotics are used in hog production and how this changed between 2004 and 2009. This study also uses a sample-selection model to examine the impact that use has on the productivity of U.S. hog operations. Using hog producer data from 2004, the analysis did not find a relationship between productivity and sub-therapeutic antibiotics fed during finishing, but productivity was significantly improved when fed to nursery pigs. These results are being evaluated... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Antibiotics; Hogs; Sample selection; Farm Management; Production Economics. |
| Ano: 2011 |
URL: http://purl.umn.edu/103232 |
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| Rao, Elizaphan J.O.; Qaim, Matin. |
| Expansion of supermarkets in developing countries is increasingly providing opportunities for farmers to participate in modern supply chains. While some farmers are excluded by stringent supermarket requirements, there are important gains for participating farmers. However, studies analyzing income effects of high-value chains use approaches that either show no causality or ignore structural differences between farmers in different channels. Using endogenous switching regression and data from a survey of vegetable growers in Kenya, we account for systematic differences and show that participation in supermarket chains yields 50% gain in household income leading to 33% reduction in poverty. Supermarket expansion is therefore likely to have substantial... |
| Tipo: Journal Article |
Palavras-chave: Supermarkets; Per capita income; Sample selection; Endogenous switching regression; Kenya; Africa; Agribusiness; Food Security and Poverty. |
| Ano: 2010 |
URL: http://purl.umn.edu/95771 |
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| Miranda, Alfonso; Rabe-Hesketh, Sophia. |
| Studying behavior in economics, sociology, and statistics often involves fitting models in which the response variable depends on a dummy variable—also known as a regime-switch variable—or in which the response variable is observed only if a particular selection condition is met. In either case, standard regression techniques deliver inconsistent estimators if unobserved factors that affect the response are correlated with unobserved factors that affect the switching or selection variable. Consistent estimators can be obtained by maximum likelihood estimation of a joint model of the outcome and switching or selection variable. This article describes a “wrapper” program, ssm, that calls gllamm (Rabe-Hesketh, Skrondal, and Pickles, GLLAMM Manual [University... |
| Tipo: Journal Article |
Palavras-chave: Endogenous switching; Sample selection; Binary variable; Count data; Ordinal variable; Probit; Poisson regression; Adaptive quadrature; Gllamm; Wrapper; Ssm; Research Methods/ Statistical Methods. |
| Ano: 2006 |
URL: http://purl.umn.edu/117582 |
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| Miranda, Alfonso. |
| This paper presents code for fitting a FIML endogenous switching Poisson count model for cross-sectional data in Stata 7: the espoisson command. The Poisson process depends on an unobserved heterogeneity term, ε; a set of explanatory variables, x; and an endogenous dummy, d. The endogenous dummy depends on an unobserved random term, v. Correlation between ε and v is allowed. If a model with exogenous d is fitted instead, correlation between ε and v will result in simultaneous equation bias. The endogenous switching model corrects this problem. After describing the underlying econometric theory behind the command, an example is discussed. |
| Tipo: Journal Article |
Palavras-chave: Count models; Endogenous switch; Sample selection; Research Methods/ Statistical Methods. |
| Ano: 2004 |
URL: http://purl.umn.edu/116208 |
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| Koundouri, Phoebe; Nauges, Celine. |
| In the estimation of production functions, ignoring risk considerations can cause inefficient estimates, while biased parameter estimates arise in the presence of sample selection. In the presence of uncertainty and selection bias, the latter introduced by the endogeneity of qualitative characteristics of inputs in crop choice, we show that correcting for risk considerations (a la Just and Pope, 1978, 1979) but not selection bias, can produce incorrect inferences in terms of risk behavior. The arguments raised in this study have estimation and policy implications for stochastic production analysis applied to all goods whose qualitative characteristics can affect sample selection. |
| Tipo: Journal Article |
Palavras-chave: Crop choice; Production risk; Sample selection; Production Economics. |
| Ano: 2005 |
URL: http://purl.umn.edu/30977 |
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| Roberts, Roland K.; English, Burton C.; Larson, James A.; Cochran, Rebecca L.; Goodman, W. Robert; Larkin, Sherry L.; Marra, Michele C.; Martin, Steven W.; Shurley, W. Donald; Reeves, Jeanne M.. |
| Probit analysis identified factors that influence the adoption of precision farming technologies by Southeastern cotton farmers. Younger, more educated farmer who operated larger farms and were optimistic about the future of precision farming were most likely to adopt site-specific information technology. The probability of adopting variable-rate input application technology was higher for younger farmers who operated larger farms, owned more of the land they farmed, were more informed about the costs and benefits of precision farming, and were optimistic about the future of precision farming. Computer use was not important, possibly because custom hiring shifts the burden of computer use to agribusiness firms. |
| Tipo: Journal Article |
Palavras-chave: Cotton; Grid soil sampling; Precision farming; Probit; Sample selection; Site-specific information; Technology adoption; Variable-rate application; D21; Q12; Q16. |
| Ano: 2004 |
URL: http://purl.umn.edu/42943 |
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| Andersson, Fredrik Ca. |
| This paper provides an empirical analysis of adjustments of land use as a result of the conversion programme in the Swedish agricultural reform of 1990. The determinants of farmers' choice to voluntarily convert arable land to other uses and the share of land converted are analysed with the Heckman selection model. The results suggest that the decision to convert is significantly affected by a farmer's age, the size and location of the farm, the type of farming, and the macroeconomic situation in the region. Farm operators on farms highly specialised in grazing livestock and farmers on large farms were found to be more prone to convert. |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Sample selection; Agricultural reform; Sweden; Set aside; MTR; Agricultural and Food Policy; Q15; Q18. |
| Ano: 2005 |
URL: http://purl.umn.edu/24706 |
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| Registros recuperados: 22 | |
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