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	Provedor de dados AgEcon (2) R. Bras. Zootec. (1) Autor Cranfield, John A.L. (2) Haq, Zahoor Ul (2) Meilke, Karl D. (2) Cazares,Aleida Selene Hernández (1) Damián,Miguel Ángel Martínez (1) Delgado,Ricardo Tellez (1) Flores,José Saturnino Mora (1) Mata,Roberto García (1) Mais... Palavra-chave Marginal effects (3) Agricultural and Food Policy (2) Agrifood Trade (2) Demand and Price Analysis (2) Gravity model (2) Heckman Selection Model (2) International Relations/Trade (2) Selection bias (2) Consumer perception (1) Logit (1) Pork meat (1) Probit (1) Research Methods/ Statistical Methods (1) Mais... Tipo do documento Working or Discussion Paper (2) Info:eu-repo/semantics/article (1) Ano 2018 (1) 2011 (1) 2010 (1) País United States (2) Brazil (1) Idioma Inglês (3)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 3 Primeira ... 1 ... Última The Gravity Model and the Problem of Zero`s in Agrifood Trade AgEcon Haq, Zahoor Ul; Meilke, Karl D.; Cranfield, John A.L.. and this is a problem when estimating log-linear gravity equations. This has caused many researchers to either ignore the zero trade flows or to replace the zero with a small positive number. Both of these actions bias the resulting parameter estimates of the gravity equation. In this study we correct for this misspecification by using the Heckman selection model to estimate bilateral trade flows for 46 agrifood products, for the period 1990 to 2000, for 52 countries. In our sample, selection bias rarely affects the signs of variables but often has a substantial effect on the magnitude, statistical significance and economic interpretation of the marginal effects. Hence, treating zero trade flows properly is important from both a statistical and an... Tipo: Working or Discussion Paper Palavras-chave: Gravity model; Selection bias; Agrifood Trade; Heckman Selection Model; Marginal effects; Agricultural and Food Policy; Demand and Price Analysis; International Relations/Trade; Research Methods/ Statistical Methods. Ano: 2011 URL: http://purl.umn.edu/116851 Does the Gravity Model Suffer from Selection Bias? AgEcon Haq, Zahoor Ul; Meilke, Karl D.; Cranfield, John A.L.. When analyzing bilateral trade flow data, zero trade flows are quite common and problematic when a gravity equation is estimated with a log-linear functional form. This has caused many researchers to either ignore the zero trade flows or to replace zero with a small positive number. Both of these actions bias the resulting parameter estimates of the gravity equation. In this study we correct for this misspecification by using the Heckman selection model to estimate the bilateral trade flows for 46 agrifood products, for the period 1990 to 2000, for 52 countries. In our sample, selection bias rarely affects the signs of variables but often has a substantial effect on the magnitude, statistical significance and economic interpretation of the marginal... Tipo: Working or Discussion Paper Palavras-chave: Gravity model; Selection bias; Agrifood Trade; Heckman Selection Model; Marginal effects; Agricultural and Food Policy; Demand and Price Analysis; International Relations/Trade. Ano: 2010 URL: http://purl.umn.edu/90884 Characterization of factors determining the consumption of pork in the Metropolitan Area of the Valley of Mexico R. Bras. Zootec. Delgado,Ricardo Tellez; Flores,José Saturnino Mora; Damián,Miguel Ángel Martínez; Cazares,Aleida Selene Hernández; Mata,Roberto García. ABSTRACT The objective of the present study was to learn the characteristics that affect pork meat consumption in the Valley of Mexico Metropolitan Area. Qualitative regression models (Logit and Probit) were used, and a survey of 440 consumers was carried out. The results showed that the sample of pork consumers was made up mostly of women (91.1%) aged between 30 and 59 years and families consisting of three or four persons. The variables that condition the consumption of this type of meat are the number of members in the family, generalized chicken meat consumption, level of household income, price of the product, and illnesses that restrict its consumption. The greatest marginal effects were caused by the following variables: level of family income and... Tipo: Info:eu-repo/semantics/article Palavras-chave: Consumer perception; Logit; Marginal effects; Pork meat; Probit. Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-35982018000100709 Registros recuperados: 3 Primeira ... 1 ... Última

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