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

Yu, Tian; Babcock, Bruce A..

We estimate impacts of rainfall and temperature on corn yields by fitting a linear spline model with endogenous thresholds. Using Gibbs sampling and the Metropolis - Hastings algorithm, we simultaneously estimate the thresholds and other model parameters. A hierarchical structure is applied to capture county-specific factors determining corn yields. Results indicate that impacts of both rainfall and temperature are nonlinear and asymmetric in most states. Yield is concave in both weather variables. Corn yield decreases significantly when temperature increases beyond a certain threshold, and when the amount of rainfall decreases below a certain threshold. Flooding is another source of yield loss in some states. A moderate amount of heat is beneficial to...

Bid-Ask Spreads, Volume, and Volatility: Evidence from Livestock Markets

Palavras-chave: Bayesian estimation; Gibbs sampler; Hierarchical structure; Metropolis-Hastings algorithm; Non-linear; Crop Production/Industries; Production Economics; Risk and Uncertainty.

Ano: 2011

URL: http://purl.umn.edu/103915

Frank, Julieta; Garcia, Philip.

Understanding the determinants of liquidity costs in agricultural futures markets is hampered by a need to use proxies for the bid-ask spread which are often biased, and by a failure to account for a jointly determined micro-market structure. We estimate liquidity costs and its determinants for the live cattle and hog futures markets using alternative liquidity cost estimators, intraday prices and micro-market information. Volume and volatility are simultaneously determined and significantly related to the bid-ask spread. Daily volume is negatively related to the spread while volatility and volume per transaction display positive relationships. Electronic trading has a significant competitive effect on liquidity costs, particularly in the live cattle...

Bayesian estimation of non-stationary Markov models combining micro and macro data

Palavras-chave: Bayesian estimation; Bid-ask spread determinants; Liquidity cost; Livestock Production/Industries; Marketing.

Ano: 2009

URL: http://purl.umn.edu/49575

Storm, Hugo; Heckelei, Thomas.

In this poster a Bayesian estimation framework for a non-stationary Markov model is developed for situations where sample data with observed transition between classes (micro data) and aggregate population shares (macro data) are available. Posterior distributions on transition probabilities are derived based on a micro based prior and a macro based Likelihood function thereby consistently combining previously separated approaches. Monte Carlo simulations for ordered and unordered Markov states show how observed micro transitions improve precision of posterior knowledge as the sample size increases.

Measuring Liquidity Costs in Agricultural Futures Markets

Palavras-chave: Bayesian estimation; Markov transitions; Prior information; Multinomial logit; Ordered multinomial logit; Agricultural and Food Policy; Research Methods/ Statistical Methods.

Ano: 2011

URL: http://purl.umn.edu/103645

Frank, Julieta; Garcia, Philip.

Estimation of liquidity costs in agricultural futures markets is challenging because bid-ask spreads are usually not observed. Spread estimators that use transaction data are available, but little agreement exists on their relative accuracy and performance. We evaluate four conventional and a recently proposed Bayesian estimators using simulated data based on Roll’s standard liquidity cost model. The Bayesian estimator tracks Roll’s model relatively well except when the level of noise in the market is large. We derive an improved estimator that seems to have a higher performance even under high levels of noise which is common in agricultural futures markets. We also compute liquidity costs using data for hogs and cattle futures contracts trading on the...

EXCISE TAXES AND COMMODITY PROMOTION: BAYESIAN RETRIEVAL OF THE OPTIMUM

Palavras-chave: Liquidity costs; Bid-ask spread; Bayesian estimation; Gibbs sampler.

Ano: 2007

URL: http://purl.umn.edu/37572

THE HEALTH EFFECTS OF A FISCAL FOOD POLICY

Holloway, Garth J..

This article shows how the solution to the promotion problem--the problem of locating the optimal level of advertising in a downstream market--can be derived simply, empirically, and robustly through the application of some simple calculus and Bayesian econometrics. We derive the complete distribution of the level of promotion that maximizes producer surplus and generate recommendations about patterns as well as levels of expenditure that increase net returns. The theory and methods are applied to quarterly series (1978:2S1988:4) on red meats promotion by the Australian Meat and Live-Stock Corporation. A slightly different pattern of expenditure would have profited lamb producers.

Tipo: Journal Article

Palavras-chave: Bayesian estimation; Commodity promotion as an experiment; Distribution of the optimum; Taylor-series expansion; Livestock Production/Industries; Marketing.

Ano: 2000

URL: http://purl.umn.edu/14660

Salois, Matthew J.; Tiffin, J. Richard.

This paper examines the health effects of a fiscal food policy based on a combination of fat taxes and thin subsidies. The fat tax is based on the saturated fat content of food items while the thin subsidy is applied to select fruit and vegetable items. The policy is designed to be revenue neutral so that the subsidy exactly offsets the revenue from the fat tax. A model of food demand is estimated using Bayesian methods that accounts for censoring and infrequency of purchase (the problem of unit values is also discussed). The estimated of demand elasticities are used to compute nutrient elasticities which demonstrate how consumption of specific nutrients changes based on price changes in particular foods from the fiscal policy. Results show that while the...

Regional crop supply behaviour in the EU

Palavras-chave: Bayesian estimation; Censoring; Fat tax; Infrequency of purchase; Nutrient elasticities; Obesity; Thin subsidy; Unit values; Agricultural and Food Policy; Consumer/Household Economics; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Food Security and Poverty; Health Economics and Policy; D30; D60; H20; I10; I30.

Ano: 2010

URL: http://purl.umn.edu/116394

Jansson, Torbjorn; Heckelei, Thomas.

The objective of this paper is to present an evolution of PMP model suitable to estimate the revenue function and to provide price elasticity due to the variation of subsidies at farm level, especially if they are decoupled. This problem arises when individual data of farm households in a given region, coming from FADN, are used for implement PMP models finalized to policy analysis. This paper presents the theoretical background of the proposed innovations and empirical evidence on the basis of a sample of farms included in FADN database in Italy.

Bayesian Estimation of Technical Efficiency of a Single Input

Palavras-chave: Bayesian estimation; Errors-in-variables; PMP; Crop Production/Industries.

Ano: 2008

URL: http://purl.umn.edu/44009

Kurkalova, Lyubov A.; Carriquiry, Alicia L..

We propose estimation of a stochastic production frontier model within a Bayesian framework to obtain the posterior distribution of single-input-oriented technical efficiency at the firm level. The proposed method is applicable to the estimation of environmental efficiency of agricultural production when the technology interaction with the environment is modeled via public inputs such as soil quality and environmental conditions. All computations are carried out using Markov chain Monte Carlo methods. We illustrate the approach by applying it to production data from Ukrainian collective farms.

Incorporating Collateral Information Using an Adaptive Management Framework for the Regulation of Transgenic Crops

Palavras-chave: Stochastic production frontier; Bayesian estimation; Input efficiency; Environmental efficiency; Crop Production/Industries.

Ano: 2000

URL: http://purl.umn.edu/18545

Linacre, Nicholas A.; Burgman, Mark A.; Ades, Peter K.; Stewart-Oaten, Allen.

A lack of data often makes biological management decisions difficult and has been an area of contention in the debate over the approval of transgenic crops. Our knowledge of natural systems is limited and our ability to gain additional information, quickly and effectively, is often handicapped by statistical complexity. To adequately cope with this requires new approaches and models that integrate decision-making and management. This paper describes one possible approach to the integration of decision-making and management, which may have application for the regulatory approval of transgenic crops. In many situations countries wishing to approve transgenic crops will have limited data on the environmental performance of the crop. The approach outlined in...

Estimation of supply response in CAPRI

Palavras-chave: Bayesian estimation; Collateral data; Inference; GMO; Transgenic plants; Bayesian theory; Biotechnology; Biosafety; Regulatory systems; Crop Production/Industries.

Ano: 2005

URL: http://purl.umn.edu/59233

Jansson, Torbjorn.

The primary objective of this paper is to estimate behavioural parameters of the quadratic regional supply models in the modelling system CAPRI, using the time series data in the CAPRI database. A secondary objective is to replace the constant yields of the original model by functions that depend on input use. Due to lack of statistical robustness, the second objective is not achieved, thus yields remain constant. A Bayesian highest posterior density estimator is developed to address the primary objective. After discarding regions with insufficient data, parameters for up to 23 crop production activities with related inputs, outputs, prices and behavioural functions are estimated for 165 regions in EU-15. The results are systematically compared to the...