SABIIA - Sistema Aberto e Integrado de Informação em Agricultura (Sabiia)

Judge, George G.; Mittelhammer, Ronald C..

When there is uncertainty concerning the appropriate statistical model to use in representing the data sampling process and corresponding estimators, we consider a basis for optimally combining estimation problems. In the context of the multivariate linear statistical model, we consider a semi-parametric Stein-like (SPSL) estimator, ...that shrinks to a random data-dependent vector and, under quadratic loss, has superior performance relative to the conventional least squares estimator. The relationship of the SPSL estimator to the family of Stein estimators is noted and risk dominance extensions between correlated estimators are demonstrated. As an application we consider the problem of a possibly ill-conditioned design matrix and devise...

Censored Probit Estimation with Correlation near the Boundary: A Useful Reparameteriztion

Palavras-chave: Stein-like shrinkage; Quadratic loss; Ill-conditioned design; Semiparametric estimation and inference; Data dependent shrinkage vector; Asymptotic and finite sample risk.; Research Methods/ Statistical Methods; Cl0; C24.

Ano: 2003

URL: http://purl.umn.edu/25103

Terza, Joseph V.; Tsai, Wei-Der.

The conventional computational algorithms for full information maximum likelihood (FIML) estimation of the censored probit model (see Farber, 1983), will sometimes fail to converge when the estimated value of the correlation coefficient (ñ) approaches ±1; even when the true value of ñ is not at a boundary. We show that a simple reparametrization of the censored probit model may afford straightforward Newton-Raphson convergence to the true FIML estimate for cases in which likelihood maximization under the conventional censored probit parameterization would have failed. Moreover, our method avoids the computational and inferential complications that arise in alternative methods that, based on a specified criterion, suggest fixing the estimated value of ñ at...

Tipo: Journal Article

Palavras-chave: Sample selection; Endogenous treatment effects; Endogenous switching; Qualitative dependent variables; Informal elderly care; Research Methods/ Statistical Methods; I12; C24; C63.

Ano: 2006

URL: http://purl.umn.edu/50278

Commercialization of Smallholders: Is Market Participation Enough?

Gebremedhin, Berhanu; Jaleta, Moti.

The literature on commercial transformation of smallholders makes little distinction between market orientation (production decision based on market signals) and market participation (sale of output). However, policy implications to enhance commercial transformation of subsistence agriculture drawn from the analysis of the determinants of household market participation alone could be inadequate, if in fact, the determinants of market orientation and market participation are not the same or not consistent with each other. This paper analyzes the determinants of market orientation and market participation in Ethiopia separately and examines if market orientation translates into market participation. Empirical results show that the determinants of market...

Tipo: Journal Article

Palavras-chave: Commercialization; Smallholders; Market orientation; Market participation; Marketing; C21; C24; Q12; Q13.

Ano: 2010

URL: http://purl.umn.edu/96159

Consumer Interest in Environmentally Beneficial Chicken Feeds: Comparing High Available Phosphorus Corn and Other Varieties

Pesek, John D., Jr.; Bernard, John C.; Gupta, Meeta.

One source of phosphorous pollution in areas of high chicken production is runoff from fields using fertilizer from these operations. A potential solution is to feed chicken high available phosphorus (HAP) corn, reducing phosphorus in manure. This study examined consumer purchase likelihood of chickens fed HAP, created traditionally or through genetic modification, and other genetically modified (GM) corn including Bt and Roundup-ready. Survey results from the Delmarva Peninsula found considerable interest in non-GM HAP corn, although GM HAP corn was not typically viewed as more acceptable than other GM varieties. Overall, the marketplace appears open to products geared toward environmental benefits.

Tipo: Journal Article

Palavras-chave: Chicken; Conjoint analysis; Corn; Genetically modified; Heteroscedastic; Phosphorus pollution; Tobit; Environmental Economics and Policy; Q13; D12; C24.

Ano: 2011

URL: http://purl.umn.edu/117945

Consumer Likelihood to Purchase Chickens with Novel Production Attributes

Bernard, John C.; Pesek, John D., Jr.; Pan, Xiqian.

Typical supermarket chickens are produced with novel or controversial attributes. This continues despite contrasting growth in consumer interest in organic and natural foods. This study surveyed Delaware consumers’ likelihood to purchase chicken given different attributes: free range, given antibiotics, irradiated, fed genetically modified (GM) fee, GM chicken, and price. Examining conjoint analysis data with a heteroskedastic two-limit tobit model, GM chicken and other novel attributes were found to lower purchase likelihood significantly. Understanding these results should help the industry meet consumer preferences while aiding its continued expansion to benefit workers and growers across the South.

Tipo: Journal Article

Palavras-chave: Antibiotics; Chicken; Conjoint analysis; Genetically modified; Heteroskedastic; Irradiated; Tobit; Consumer/Household Economics; Food Consumption/Nutrition/Food Safety; Q13; D12; C24.

Ano: 2007

URL: http://purl.umn.edu/6058

Consumer Surplus Estimates and the Source of Regression Error

Beatty, Timothy K.M.; Brozovic, Nicholas; Ward, Michael B..

Contrary to widely held belief, we show that the source of regression error does not matter when calculating Marshallian surplus. A misspecified demand curve, not the assumed source of regression error, leads to differences in estimates of consumer surplus.

COST EFFICIENCY OF CATFISH FARMS IN CHICOT COUNTY, ARKANSAS: THE IMPACT OF EXTENSION SERVICES

Palavras-chave: Regression Error; Marshallian Surplus; Welfare Analysis; Consumer/Household Economics; D60; C24; Q51.

Ano: 2005

URL: http://purl.umn.edu/19477

Engle, Carole R.; Kaliba, Aloyce R..

Cost efficiency measures of a sample of catfish farms in Chicot County, Arkansas are estimated using a data envelopment analysis technique. A measure of overall efficiency is used to determine operator's characteristics, farm practices, and institutional support services that are likely to lead to higher farm level cost efficiency. Results indicate that live catfish production could increase by 55% using the same level of inputs if all farms were operating at the minimum average cost curve. Higher feeding rate and availability of extension services were associated with increased cost efficiency. Higher stocking density affected overall efficiency negatively. The marginal value of extension contacts in Chicot County was estimated to be $2988. This study...

Determinants of Malaysian Household Expenditures on Food-Away-From-Home

Palavras-chave: Catfish; Cost efficiency; Data envelopment analysis; And extension services; Resource /Energy Economics and Policy; C14; C24; D61.

Ano: 2004

URL: http://purl.umn.edu/34740

Lee, Helen; Tan, Andrew K.G..

The censored Tobit model is applied on data from the Malaysian Household Expenditure Survey (1998/99) to identify socio-demographic determinants of household expenditures on food-away-from-home (FAFH). Results indicate that Chinese, urban residents, and those with higher monthly household income spend significantly more on FAFH expenditures than their non-Chinese, rural, and lower household income cohorts, ceteris paribus. Other results obtained suggest that age of household head, gender, education level and household size do not significantly affect household expenditures on FAFH. Based on the above findings, several observations are noted. First, the current range of menus being served can be further diversified in order to attract those with religious...

Determinants of smallholders’ decisions to leave land fallow: the case of Kosovo

Palavras-chave: Censored demand; Household-expenditures; Food-away-from-home; Malaysia; Socio-demographics; Food Consumption/Nutrition/Food Safety; L66; C24; D12.

Ano: 2006

URL: http://purl.umn.edu/25430

Sauer, Johannes; Davidova, Sophia; Latruffe, Laure.

The objective of this article is to investigate why farmers in Kosovo leave land fallow when the total land of their farms is small and households, almost fully dependent on farming for their livelihoods, are large. In order to elicit some of the barriers to land utilization, the article uses a comprehensive survey carried out during the agricultural year 2005/2006 to explore agricultural households’ perceptions of production, market conditions, and general security six years after the end of the military conflict in the former Yugoslavia. Several agro-environmental, household and farm characteristics are employed to empirically approximate the significance of different factors for leaving land fallow. Three different econometric models are used to address...

DETERMINANTS OF THE DEMAND FOR ORGANIC AND CONVENTIONAL FRESH MILK IN GERMANY– AN ECONOMETRIC ANALYSIS

Palavras-chave: Fallow land decision; Kosovo; Endogeneity; Community/Rural/Urban Development; C24; Q12; Q15.

Ano: 2010

URL: http://purl.umn.edu/94917

Schrock, Rebecca.

An increasing number of studies deals with consumer decisions regarding organic food, but only a few provide quantitative estimates of price and income elasticities. This paper contributes to the existing literature by providing own-price elasticity estimates as well as an analysis of the sociodemographic determinants of demand for organic milk. The analysis is based on the GfK Consumer Scan Scanner panel dataset on food purchases of German households covering a sample period of four years from 2004 to 2007. A two-step estimation procedure is applied. First, a probit regression examines which household characteristics affect the probability to buy organic milk. Second, a fixed-effects panel regression determines factors that have an impact on the quantity...

Educational Function of Agriculture and Farm Diversification: Evidence from Dairy Farming Experience Services in Japan

Palavras-chave: Organic milk; Household Panel; Probit Analysis; Fixed-Effects-Panel Analysis; Price elasticity; Private-labels; Germany; Agricultural and Food Policy; Consumer/Household Economics; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Food Security and Poverty; Health Economics and Policy; C23; C24; C25; D12; M31; Q11.

Ano: 2010

URL: http://purl.umn.edu/116387

Ohe, Yasuo.

To promote multifunctional activity, it is crucial to clarify how jointness is formed in connection with farm structure. This paper examines the relationship between multifunctional activity and farm structure by focusing on the educational function of dairy farming, i.e., farming experience services, in Japan. The main findings were as follows. First, from our conceptual consideration we can say that the educational function is determined by technical and institutional jointness and there is a U-shaped relationship between farm diversification and provision of farming experience services. In addition, the national program aimed at promoting this educational function was effective in enhancing this function. Second, however, from the empirical evaluation...

Empirical Evidence Concerning the Finite Sample Performance of EL-Type Structural Equation Estimation and Inference Methods

Palavras-chave: Multifunctionality; Educational function; Farm diversification; Environmental Economics and Policy; Farm Management; Livestock Production/Industries; Q12; Q26; Q57; C24.

Ano: 2009

URL: http://purl.umn.edu/51557

Mittelhammer, Ronald C.; Judge, George G.; Schoenberg, Ron.

This paper presents empirical evidence concerning the finite sample performance of conventional and generalized empirical likelihood-type estimators that utilize instruments in the context of linear structural models characterized by endogenous explanatory variables. There are suggestions in the literature that traditional and non-traditional asymptotically efficient estimators based on moment equations may, for the relatively small sample sizes usually encountered in econometric practice, have relatively large biases and/or variances and provide an inadequate basis for estimation and inference. Given this uncertainty we use a range of data sampling processes and Monte Carlo sampling procedures to accumulate finite sample empirical evidence concerning...

Estimating Farm Efficiency in the Presence of Double Heteroscedasticity Using Panel Data

Palavras-chave: Unbiased moment based estimation and inference; Empirical likelihood; Empirical exponential likelihood; Semiparametric models; Conditional estimating equations; Finite sample bias and precision; Squared error loss; Instrumental conditioning variables; Research Methods/ Statistical Methods; C10; C24.

Ano: 2003

URL: http://purl.umn.edu/25090

Hadri, Kaddour; Guermat, Cherif; Whittaker, Julie.

The accuracy of technical efficiency measures is important given the interest in such measures in policy discussions. In recent years the use of stochastic frontiers has become popular for estimating technical inefficiency, but estimated inefficiencies are sensitive to specification errors. One source of such errors is heteroscedasticity. This paper addresses this issue by extending the Hadri (1999) correction for heteroscedasticity to stochastic production frontiers and to panel data. It is argued that heteroscedasticity within an estimation can have a significant effect on results, and that correcting for heteroscedasticity yields more accurate measures of technical inefficiency. Using panel data on cereal farms, it is found that the usual technical...

Tipo: Journal Article

Palavras-chave: Stochastic frontier production; Heteroscedasticity; Technical efficiency; Panel data; Farm Management; Research Methods/ Statistical Methods; C23; C24; D24; Q12.

Ano: 2003

URL: http://purl.umn.edu/43994

Estimating the Link Function in Multinomial Response Models under Endogeneity and Quadratic Loss

Judge, George G.; Mittelhammer, Ronald C..

This paper considers estimation and inference for the multinomial response model in the case where endogenous variables are arguments of the unknown link function. Semiparametric estimators are proposed that avoid the parametric assumptions underlying the likelihood approach as well as the loss of precision when using nonparametric estimation. A data based shrinkage estimator that seeks an optimal combination of estimators and results in superior risk performance under quadratic loss is also developed.

EU policy reform simulation based on panel data estimation of on- and off-farm labour supply equations for Dutch dairy farmers

Palavras-chave: Multinomial Process; Endogeneity; Empirical likelihood procedures; Quadratic loss; Semiparametric estimation and inference; Data dependent shrinkage; Asymptotic and finite sample risk; Research Methods/ Statistical Methods; C10; C24.

Ano: 2004

URL: http://purl.umn.edu/25095

Ooms, Daan L.; Hall, Alastair R..

This research focuses on the estimation of labour supply equations for Dutch dairy farmers that are suitable for policy simulations. Data availability leads to the fact that we can not estimate structural labour supply equations. We show how to derive reduced form equations suitable for policy simulations. In this research we use the panel data sample selection estimation approach of Kyriazidou (1997) and Wooldridge (1995) to estimate the off-farm labour supply equation. The two lead to different estimation results and different simulation results based on these.

Impacts of Sample Size and Quality-Adjusted Imputed Prices on Own-Price Elasticities Estimated Using Cross-Sectional Data

Palavras-chave: Econometrics; Panel Data; Sample Selection; Labour Supply; CAP Reform; Labor and Human Capital; C23; C24; C51; C53; D13; J22; Q12; Q18.

Ano: 2005

URL: http://purl.umn.edu/19434

Incorporating Uncertainty and Cero Values into the Valuation of Protected Areas and Species

Stockton, Matthew C..

Cross-sectional data sets containing expenditure and quantity information are typically used to calculate quality-adjusted imputed prices. Do sample size and quality adjustment of price statistically alter estimates for own-price elasticities? This paper employs a data set pertaining to three food categories-pork, cheese, and food away from home-with four sample sizes for each food category. Twelve sample sizes were used for both adjusted and unadjusted prices to derive elasticities. No statistical differences were found between own-price elasticities among sample sizes. However, elasticities that were based on adjusted price imputations were significantly different from those that were based on unadjusted prices.

Tipo: Journal Article

Palavras-chave: Cross-sectional data; Imputed prices; Quality-adjusted prices; B41; D12; C21; C24.

Ano: 2003

URL: http://purl.umn.edu/43216

Hurle, Jesus Barreiro; Garcia, Jose Maria Casada; Perez y Perez, Luis.

Under the Spanish conservation law, compensation is envisaged for the damage associated with all actions that reduce the quantity or quality of protected areas and species. This paper provides a tool to evaluate the monetary equivalent of this damage. We conduct a contingent valuation exercise to estimate the existence value related to protected areas and species in Aragon. This estimate is then reconsidered including the possibility of zero bids and also the possibility of uncertain preferences for non-familiar goods. Considering these two effects, mean values are reduced significantly giving support to previous recommendations of dividing by two contingent valuation estimates from dichotomous choice question formats.

Measurement and Political Economy of Disputed Technical Regulations

Palavras-chave: Natural heritage; Contingent valuation; Spike model; Uncertainty; Land Economics/Use; B23; C24; C42; C52; D62; Q26.

Ano: 2005

URL: http://purl.umn.edu/24745

Thornsbury, Suzanne; Roberts, Donna; Orden, David.

Technical regulations are increasingly visible in agricultural trade, yet their idiosyncratic nature has limited prior aggregate analysis. This article draws on a unique data source for systematic enumeration of the technical regulations questioned by one exporter among all of its trading partners in mid-1996. Political economy analysis indicates that barriers decrease when the relative contribution of agriculture to an economy increases, when the anticipated future level of protection through other forms of government intervention increases, and when economies are more open. Despite increased scrutiny and discipline by the World Trade Organization, technical barriers remain a significant impediment in world agricultural markets.

Tipo: Journal Article

Palavras-chave: Limited dependent variable; Sanitary; And phytosanitary; WTO; F13; F14; C21; C24.

Ano: 2004

URL: http://purl.umn.edu/43448

Measuring the Determinants of School Completion in Pakistan: Analysis of Censoring and Selection Bias

Holmes, Jessica.

This paper explores the demand for child schooling in Pakistan, using the Pakistan Integrated Household Survey (1991). There have been few such studies for Pakistan, a country with relatively low enrollment rates and education levels, high illiteracy, and large disparity between male and female education. Additionally, this study focuses on two potential sources of bias in the estimation of the demand for schooling. First, studies which do not distinguish between currently enrolled children and those who have completed their schooling subject their estimates to a form of censoring bias. Second, studies which exclude children who have left the household from their samples may introduce sample selection bias if the decisions to leave home and to attend...

On- and Off-Farm Labour Supply of Dutch Dairy Farmers: Estimation and Policy Simulations

Palavras-chave: Labor and Human Capital; I2; C24.

Ano: 1999

URL: http://purl.umn.edu/28530

Ooms, Daan L.; Hall, Alastair R..

This research focuses on the effect of decoupled payments on labour supply of Dutch dairy farmers. Data availability leads to the fact that we can not estimate structural labour supply equations. We show how to derive reduced form equations suitable for policy simulations. We use the panel data sample selection estimation approach Wooldridge (1995) to estimate the off-farm labour supply equation. This method is based on Mundlak's (1978) linear panel data estimation approach, which we use to estimate the on-farm labour supply equations. Even though, simulations show a significant negative effect of decoupled payments on labour supply, the economic significance of this effect is very limited.