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

Estimation of Treatment Effect of Asthma Case Management Using Propensity Score Methods

Hudson, Darren.

The roots and uses of economic experiments in problem solving and hypothesis testing are explored in the present article. The literature suggests that the primary advantage of economics experiments is the ability to use controlled stimuli to test economic hypotheses. Other literature also suggests that experiments are useful in problem solving settings. The advantages and disadvantages of experiments are discussed.

Tipo: Journal Article

Palavras-chave: Experiments; Problem solving; Hypothesis testing; C81; C91; C92; C93.

Ano: 2003

URL: http://purl.umn.edu/43209

Brandt, Sylvia J.; Gale, Sara; Tager, Ira.

Objective: To estimate the treatment effect from participating in an asthma intervention that was part of the National Asthma Control Program. Study Setting: Data on children who participated in asthma case management (N=270) and eligible children who did not participate in case management (N=2,742) were extracted from a claims database. Study Design: We created 81 measures of health care utilization and 40 measures of neighborhood characteristics that could be related to participation in the program. The participation model was selected using the cross-validation-based Deletion Substitution and Addition (DSA) algorithm. We used optimal full matching for the vector of Mahalanobis’ distances and propensity scores to estimate the difference between...

Inside the 'Black Box' of Project Star: Estimation of Peer Effects Using Experimental Data

Palavras-chave: Asthma; Treatment effect; Health intervention; Propensity scores; Consumer/Household Economics; Health Economics and Policy; Research Methods/ Statistical Methods; I1; D13; H51; C31; C80; C81; C83.

Ano: 2009

URL: http://purl.umn.edu/53124

Boozer, Michael A.; Cacciola, Stephen E..

The credible identification of endogenous peer group effects i.e. social multiplier or feedback effects has long eluded social scientists. We argue that such effects are most credibly identified by a randomly assigned social program which operates at differing intensities within and between peer groups. The data we use are from Project STAR, a class size reduction experiment conducted in Tennessee elementary schools. In these data, classes were comprised of varying fractions of students who had previously been exposed to the Small class treatment, creating class groupings of varying experimentally induced quality. We use this variation in class group quality to estimate the spillover effect. We find that when allowance is made for this feedback effect...

The Effects of Class Size on the Long Run Growth in Reading Abilities and Early Adult Outcomes in the Christchurch Health and Development Study

Palavras-chave: Peer effects; Data with a group structure; Organization of schooling; Experimental evidence; Teaching/Communication/Extension/Profession; Z13; C51; C81; I21; C23.

Ano: 2001

URL: http://purl.umn.edu/28524

Boozer, Michael A.; Maloney, Tim.

This paper utilizes the feature of the CHDS data from New Zealand that children are sampled for extremely long individual histories of their class size experiences as well as their scholastic and early labor market outcomes. Our interest is to explore the full set of empirical implications of the recent experimental evidence on class size effects on student achievement from the United States in Project STAR for observational data. We argue that one implication of Project STAR is that only persistent class size reduction policies may have detectable effects, and so the longitudinal aspect of CHDS is necessary to detect class size effects. We account for the observational nature of the CHDS (in that children were not randomly assigned to different class...

Forecasting the Adoption of GM Oilseed Rape: Evidence from a Discrete Choice Experiment

Palavras-chave: School quality; Value-added model; Experimental evidence; Labor and Human Capital; C51; C81; I21; C23.

Ano: 2001

URL: http://purl.umn.edu/28384

Breustedt, Gunnar; Muller-Scheessel, Jorg; Latacz-Lohmann, Uwe.

This paper explores farmers’ willingness to adopt genetically modified oilseed rape prior to its commercial release and estimates the ‘demand’ for the new technology. The analysis is based upon choice experiments with 202 German arable farmers. A multinomial probit estimation revealed that GM attributes such as gross margin, expected liability from cross pollination, or flexibility in returning to conventional oilseed rape significantly affect the likelihood of adoption. Neighbouring farmers’ attitudes towards GM cropping and a number of farmer and farm characteristics were also found to be significant determinants of prospective adoption. Demand simulations suggest that adoption rates are very sensitive to the profit difference between GM and non-GM rape...

The Economic Value of Wetland Conservation and Creation: A Meta-Analysis

Palavras-chave: Adoption forecast; Choice experiment; Genetically modified oilseed rape; Multinomial probit; Technology adoption; C42; C81; Q12; Q16.

Ano: 2008

URL: http://purl.umn.edu/36771

Ghermandi, Andrea; van den Bergh, Jeroen C.J.M.; Brander, Luke M.; de Groot, Henri L.F.; Nunes, Paulo A.L.D..

The rationale for conservation and creation of wetlands stems from the recognition of both their ecological and economic values. This paper examines the welfare impacts of goods and services provided by wetlands. We collected 385 estimates of the economic value of 181 natural and man-made wetlands from 167 studies worldwide. The resulting database is less biased towards North America than previous reviews of the literature. The relative importance of characteristics of the valuation study, of the wetland site, and of the socio-economic and geographical context is estimated by means of a meta-regression analysis of wetland values. Provision of amenities, flood control and storm buffering, and water quality improvement are the most highly valued wetland...

DOCUMENTATION OF THE POLAND FARM SURVEY 2000

Palavras-chave: Constructed Ecosystems; Economic Valuation; Man-Made Wetlands; Meta-Regression; Wetland Values; Resource /Energy Economics and Policy; C81; Q24.

Ano: 2008

URL: http://purl.umn.edu/44229

Petrick, Martin.

This documentation summarises the technical information about the Poland farm survey 2000. This survey was recently carried out in co-operation with Polish partners by the Institute of Agricultural Development in Central and Eastern Europe (IAMO) in Halle (Saale), Germany. The topics covered in the documentation are a description and reprint of the questionnaire, sample design, survey organisation and implementation, data management, calculation of certain compound variables, and a brief assessment of the experiences made with the instrument.

Documentation of a multi-topic questionnaire-based survey on sustainable resource use in rural China

Palavras-chave: Methods of data collection; Microeconomic data; Survey methodology; Research Methods/ Statistical Methods; C81.

Ano: 2001

URL: http://purl.umn.edu/14908

Jia, Xiangping; Buchenrieder, Gertrud.

This Discussion Paper documents a survey conducted in rural China in 2005. A multi-topic survey funded by the Sino-German international Training Program "Sustainable Resource Use in North China", the project covers farm management, land property rights and rural credit access on the North China Plain. From a credit standpoint, this paper covers questionnaire design, sample, survey implementation, data entry, a brief assessment of the overall experience, as well as lessons drawn.

Salvage the treasure of geographic information in Farm census data

Palavras-chave: Questionnaire; Survey; Credit access; Household model; Categorical variables; Stata.; Agribusiness; Farm Management; Food Consumption/Nutrition/Food Safety; International Development; Land Economics/Use; Productivity Analysis; Resource /Energy Economics and Policy; C81; C93; D19.

Ano: 2007

URL: http://purl.umn.edu/90856

Gocht, Alexander; Roder, Norbert.

In Germany, since several decades the RAUMIS modelling system is applied for policy impact assessments to measure the impact of agriculture on the environment. A disaggregation at the municipality level with more than 9.600 administrative units, instead of currently used 316 counties, would tremendously improve the environmental impact analysis. Two sets of data are used for this purpose. The first are geo-referenced data, that are, however, incomplete with respect its coverage of production activities in agriculture. The second set is the micro census statistic itself, that has a full coverage, but data protection rules (DPR) prohibit its straightforward use. The paper show how this bottleneck can be passed to obtain a reliable modelling data set at...

Evaluating the Impact on Market Performance of Investments in Market Information Systems: Methodological Challenges

Palavras-chave: Highest Posterior Density estimator (HPD); RAUMIS; Down scaling; Research Methods/ Statistical Methods; C11; C61; C81; Q15.

Ano: 2011

URL: http://purl.umn.edu/115982

Staatz, John M.; Kizito, Andrew M.; Weber, Michael T.; Dembele, Niama Nango.

Evaluating the impact on market performance of investments in agricultural market information systems (MIS) face several methodological challenges. These fall into two broad categories: (a) defining the dimensions of market performance to measure (which is a function of whom the MIS is designed to serve) and identifying reliable indicators of those performance dimensions, and (b) identifying the causal effects of the MIS. The determination of causal effects in turn requires establishing a credible baseline, measuring “treatment effects” (i.e., the effects on economic behavior of receiving improved information from an MIS), dealing with problems of endogenous placement of treatment, and interpreting the validity of stakeholders’ statements and...

Microeconomic and Geo-physical Data Integration for Agri-environmental Analysis, Georeferencing FADN Data: A Case Study in Italy

Palavras-chave: Market information services; Impact assessment; Market transparency; Food policies; Agricultural and Food Policy; Food Security and Poverty; International Development; Marketing; Research and Development/Tech Change/Emerging Technologies; Research Methods/ Statistical Methods; C81; D80; H43; N57; 013; Q13.

Ano: 2011

URL: http://purl.umn.edu/108184

Fais, Andrea; Nino, Pasquale; Giampaolo, Antonio.

The authors, inside a TAPAS action, have developed a methodology - based on the integration between FADN data with statistical, administrative and cartographic information - to improve the production of statistical data related to agricultural policies impact on land and environment. This methodology allows - using Geographic Information System (GIS) technology - to produce and organise data at geographical level. Data spatially referenced respond to the specific needs of agri-environmental analysis and problems, mostly related to specific areas (environmental vulnerability areas), inside defined boundaries (e.g. river basin). The GIS is implemented with several cartographic layers (Topographic and cadastral maps, land use, soils, water sources, climate,...

Modeling Advertising Expenditures and Spillover Effects Applied to the U.S. Non-Alcoholic Beverage Industry: Vector Autoregression (VAR) and Polynomial Distributed Lag (PDL) Approaches

Palavras-chave: Agricultural statistics; Agri-environment; FADN; GIS; TAPAS; DPSIR; Environmental Economics and Policy; C81; O13; Q21.

Ano: 2005

URL: http://purl.umn.edu/24547

Dharmasena, Senarath; Capps, Oral, Jr.; Bessler, David A..

The non-alcoholic beverage market in the U.S. is a multi-billion dollar industry growing steadily over the past decade. Also, non-alcoholic beverages are among the most heavily advertised food and beverage groups in the United States. Several studies pertaining to non-alcoholic beverages including the incorporation of advertising effects have been conducted, but most of these have centered attention on milk consumption. Some studies have considered demand interrelationships for several beverages including advertising effects in systems-wide analyses. In our analysis, we develop and employ a unique monthly time-series data set derived from Nielsen Homsescan panels for household purchases of non-alcoholic beverages over the period from January 1998 through...

Tipo: Presentation

Palavras-chave: Non-alcoholic beverages; Vector autoregression; Polynomial distributed lags; Beverage advertizing; Directed acyclic graphs; Agricultural and Food Policy; Consumer/Household Economics; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Marketing; C18; C22; C52; C53; C81; D11; D12.

Ano: 2012

URL: http://purl.umn.edu/124363

Canadian Consumer Attitudes and Purchasing Behaviour of Omega-3 Products

Nilsson, Tomas K.H.; Chase, Darren; Emunu, John Paul; McCann-Hiltz, Diane; Peng, Yanning.

The development of innovative functional food products is a major trend in today's food industry. The growth of this industry is driven by increased consumer awareness of their own health deficiencies, increased understanding of the possible health benefits of functional foods, development in formulation technologies, a positive regulatory environment and changing consumer demographics and lifestyles. While there has been a proliferation of omega-3 products such as milk, eggs, yogurt, and margarine in the Canadian food market, very little is known about consumers of omega-3 products. In our study we use ACNielsen HomescanTM data combined with ACNielsen Panel TrackTM survey data to develop profiles of omega-3 consumers in Canada. The focus of the study is...

Scaling up Ecosystem Services Values: Methodology, Applicability and a Case Study

Palavras-chave: Omega-3 fatty acids; Nutritional labelling; Health benefits; Ordered probit model; Food Consumption/Nutrition/Food Safety; C81; D12; I19; Q19.

Ano: 2007

URL: http://purl.umn.edu/7713

Brander, Luke M.; Ghermandi, Andrea; Kuik, Onno; Markandya, Anil; Nunes, Paulo A.L.D.; Schaafsma, Marije; Wagtendonk, Alfred.

The approach of using existing data on economic values of local ecosystem services for an assessment of these values at a larger geographical scale can be called “scaling up”. In a scaling-up exercise, economic values from a particular study site are transferred to another geographical setting, for instance to the regional, national or global scale. This paper proposes a methodology for scaling up ecosystem service values to a European level, assesses the availability of data for conducting this method, and illustrates the procedure with a case study on wetland values. The proposed methodology makes use of meta-analysis to produce a value function that is subsequently applied to individual European wetland sites. Site-specific, study-specific and...

MUNICIPALITY DISAGGREGATION OF GERMAN'S AGRICULTURAL SECTOR MODEL RAUMIS

Palavras-chave: Ecosystem Services; Value Transfer; Meta-Analysis; Wetland Values; Environmental Economics and Policy; C81; Q24; Q57.

Ano: 2010

URL: http://purl.umn.edu/60689

Roeder, Norbert; Gocht, Alexander.

Since several decades the RAUMIS modelling system is applied for policy impact assessments to measure the impact of agriculture on the environment. A disaggregation at the municipality level with more than 9.000 administrative units, instead of currently used 316 counties, would tremendously improve the environmental impact analysis. Two sets of data are used for this purpose. The first are geo-referenced data, that are, however, incomplete with respect its coverage of production activities in agriculture. The second set is the micro census statistic itself, that has a full coverage, but data protection rules (DPR) prohibit its straightforward use. The paper show how this bottleneck can be passed to obtain a reliable modelling data set at municipality...

Simplified Marginal Effects in Discrete Choice Models

Palavras-chave: Highest Posterior Density estimator (HPD); RAUMIS; Down scaling; Agricultural and Food Policy; C11; C61; C81; Q15.

Ano: 2011

URL: http://purl.umn.edu/99248

Anderson, Soren T.; Newell, Richard G..

We show that after a simple normalization of explanatory variables so that they equal zero at some desired reference point, marginal effects for continuous variables in probit and logit models simplify dramatically, becoming a function of only the estimated constant term. We present similar simplifications for computation of the asymptotic variance of marginal effects, as well as for the effects of dummy variables on predicted probabilities. We provide a simple table, which in combination with raw probit or logit estimates, is all one needs to compute the desired effects.

Determinants of Poverty among U.S. Farm Households

Palavras-chave: Logit; Probit; Discrete choice; Binary choice; Marginal effect; Data normalization; Research Methods/ Statistical Methods; C25; C51; C81.

Ano: 2003

URL: http://purl.umn.edu/10631

El-Osta, Hisham S.; Morehart, Mitchell J..

This research uses data from the 2004 Agricultural Resource Management Survey and probit regression to examine the determinants of poverty among U.S. farm households. The findings reveal, among others, the importance of a livelihood strategy that combines participation in government programs and off-farm work in lowering poverty rates. Findings also show the importance of educational attainment of the farm operator in mitigating poverty, but only when poverty is measured on a relative rather than an absolute basis. Policy recommendations are provided in the context of these findings.

Tipo: Journal Article

Palavras-chave: Composite measure of economic well-being; Government programs; Off-farm work; Poverty; Agricultural Finance; Financial Economics; Labor and Human Capital; J23; J24; D3; I21; I32; C81.

Ano: 2008

URL: http://purl.umn.edu/45037

La tipologia de las explotaciones en funcion de su viabilidad economica y demografica: aplicacion a las explotaciones de bovino en Galicia

Garcia, Francisco Sineiro; Iglesias, Edelmiro Lopez; Fernandez, Roberto Lorenzana; Pacos, Bernardo Valdes.

RESUMEN En este artículo se elabora una tipología de las explotaciones de bovino en Galicia en función de su viabilidad económica y demográfica, empleando como fuente las bases de datos anonimizadas de los censos agrarios de 1989 y 1999. Los resultados así obtenidos son utilizados en una triple dirección: ofrecer una radiografía de la estructura actual del sector, interpretar sus transformaciones recientes y proyectar las tendencias para la próxima década (1999-2009). El análisis permite concluir que el sector está integrado por tres grandes grupos de explotaciones, con unas características y unas perspectivas muy diferentes: aquéllas con viabilidad económica y demográfica, sólo 1/5 pero que concentran ya la mayor parte del output; las que están en manos...

Tipo: Journal Article

Palavras-chave: Viability of farms; Agrarian structures; Bovine livestock; Galicia; Structural adjustment; Livestock Production/Industries; C81; Q12; Q15; Q18.

Ano: 2004

URL: http://purl.umn.edu/28775

A Comparison of Imputation Methods under Large Samples and Different Censoring Levels (PowerPoint)

Lopez, Jose Antonio.

PowerPoint Presentation

Unpacking the Meaning of “Market Access”

Palavras-chave: Imputation methods; Multiple imputation; Censored prices; Protein demand; Elasticities; Demand and Price Analysis; Food Consumption/Nutrition/Food Safety; Research Methods/ Statistical Methods; C81; Q11; R21.

Ano: 2011

URL: http://purl.umn.edu/109894

Chamberlin, Jordan; Jayne, Thomas S..

Improving farmers’ access to markets is widely recognized as a major development challenge. A review of the literature suggests that indicators of market access may bear little relationship to the specific processes of interest and hence provide misguided evidence of the impacts of improved market access. This paper attempts to “unpack” the dimensions of market access and, in the process, uses farm survey data from Kenya to investigate changes in multiple indicators during the post-liberalization period. Findings show that market access conditions experienced by rural Kenyans exhibit considerable variation across time, space, and indicator type. We suggest ways in which structured hypothesizing and sensitivity analysis may strengthen empirical treatments...