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	Provedor de dados AgEcon (9) Ciencia e Investigación Agraria (1) Ecology and Society (1) Autor Breustedt, Gunnar (2) Cranfield, John A.L. (2) Haq, Zahoor Ul (2) Mees, Martin (2) Meilke, Karl D. (2) Bakucs, Lajos Zoltan (1) Benfica, Rui M.S. (1) Boughton, Duncan (1) Chiburis, Richard (1) Christy, Ralph D. (1) Donoso,Guillermo (1) Ferto, Imre (1) Islam, K.M. Zahidul (1) Lokshin, Michael (1) Mabaya, Edward T. (1) Melo,Oscar (1) Negrete,Eduardo (1) Sipilainen, Timo (1) Sumelius, John (1) Tschirley, David L. (1) Mais... Palavra-chave Selection bias (11) Agricultural and Food Policy (4) Research Methods/ Statistical Methods (4) Crop Production/Industries (3) Agrifood Trade (2) Demand and Price Analysis (2) Farm Management (2) Gibrat's Law (2) Gravity model (2) Heckman Selection Model (2) International Relations/Trade (2) Marginal effects (2) Milk quota (2) Q12 (2) Advocacy (1) Agricultural Finance (1) Bangladesh (1) C21 (1) Contract farming (1) D1 (1) Mais... Tipo do documento Conference Paper or Presentation (6) Working or Discussion Paper (2) Article (1) Journal article (1) Peer-Reviewed Reports (1) Ano 2011 (2) 2010 (4) 2007 (2) 2006 (2) 2000 (1) País United States (9) Canada (1) Chile (1) Idioma Inglês (11)		Ordenar por:  Relevância Autor Título Ano Registros recuperados: 11 Primeira ... 1 ... Última Scientific Research or Advocacy? Emotive Labels and Selection Bias Confound Survey Results Ecology and Society Vanclay, Jerome K; Southern Cross University; jvanclay@scu.edu.au. Robert Costanza presents four compelling visions of the future, but the language he uses to describe them is emotive and value-laden and may bias the survey results. The descriptions and analogies used may evoke responses from the survey participants that reveal more about their reactions to the description than their attitudes toward a given scenario. It is hypothesized that the use of more neutral language may lead to more support for the scenario involving "self-limited consumption with ample resources" that Costanza calls "Big Government." If this hypothesis is correct, then the skeptic's policy that Costanza appears to prefer has the additional advantage of always leading to the favored outcome, regardless of the state of the world. Tipo: Peer-Reviewed Reports Palavras-chave: Advocacy; Selection bias; Survey. Ano: 2000 Smallholders' Cost Efficiency in Mozambique: Implications for Improved Maize Seed Adoption AgEcon Zavale, Helder; Mabaya, Edward T.; Christy, Ralph D.. Maize is an important staple in Mozambique. It is also a dominant crop produced by smallholder farmers. However, the actual maize yields, currently estimated at 1.4 tons/ha, fall short of potential yields of 5-6.5 tons/ha. With population growth rate increasingly exceeding agricultural (and maize) productivity growth rate, the government of Mozambique faces a serious problem of food insecurity and poverty alleviation. This study examines cost inefficiency among smallholder maize farmers in Mozambique, and the impact of improved maize seed adoption on cost efficiency. A Translog functional form is used to estimate the frontier cost function. A cost-inefficiency function is used to examine the factors that determine cost inefficiency among farmers.... Tipo: Conference Paper or Presentation Palavras-chave: Stochastic frontier; Technology adoption; Selection bias; Mozambique; Crop Production/Industries; Q12; Q16; D13; O33. Ano: 2006 URL: http://purl.umn.edu/25648 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 Growth of German dairy farms under the EU milk quota AgEcon Breustedt, Gunnar; Mees, Martin. We estimate determinants of growth among German dairy farms between 1997 und 2005 under the EU milk quota system. Higher milk yield per cow, more family labour, and higher milk prices increase the growth rate of growing farms, ceteris paribus. Older growing farmers tend to grow at lower rates. In line with Weiss’ findings (1999) for Austrian farms, Gibrat’s Law of relative firm growth being independent of initial firm size does not hold for our subsample of farms growing in milk production, either: the growth rate is quite high for small farms and has a minimum for farms around 325,000 kg of initial quota. For the 16% of growing farms that have more initial quota the growth rate increases up to some out-of-sample maximum. We corrected for selection bias by... Tipo: Conference Paper or Presentation Palavras-chave: Keywords: farm growth; Gibrat’s Law; Milk quota; Multinomial logit; Selection bias; Agricultural and Food Policy; Farm Management; Land Economics/Use. Ano: 2010 URL: http://purl.umn.edu/61080 GIBRAT'S LAW REVISITED IN A TRANSITION ECONOMY. THE HUNGARIAN CASE AgEcon Bakucs, Lajos Zoltan; Ferto, Imre. The paper investigates the validity of Gibrat's Law in Hungarian agriculture. Employing various specifications including OLS, two-step Heckman model and quantile regressions our results strongly reject Gibrat’s Law for full sample. Estimations suggest that small farms tend to grow faster than larger ones. However, splitting the sample into two subgroups (corporate and family farms) we found different results. For family farms however, only OLS regression results reject Gibrat's Law, whilst the two-step Heckman models and quantile regression estimates support it. Finally, for corporate farms our results support the Law regardless of the method or size measure used. Our results indicate that there is no difference between family farms and corporate farms... Tipo: Conference Paper or Presentation Palavras-chave: Gibrat's Law; Selection bias; Quantile regression; Transition agriculture; Farm Management; Research Methods/ Statistical Methods. Ano: 2007 URL: http://purl.umn.edu/7813 Maximum likelihood and two-step estimation of an ordered-probit selection model AgEcon Chiburis, Richard; Lokshin, Michael. We discuss the estimation of a regression model with an ordered-probit selection rule. We have written a Stata command, oheckman, that computes two-step and full-information maximum-likelihood estimates of this model. Using Monte Carlo simulations, we compare the performances of these estimators under various conditions. Tipo: Article Palavras-chave: Oheckman; Selection bias; Ordered probit; Maximum likelihood; Research Methods/ Statistical Methods. Ano: 2007 URL: http://purl.umn.edu/119266 Access to Microfinance: Does it Matter for Profit Efficiency Among Small Scale Rice Farmers in Bangladesh? AgEcon Sumelius, John; Islam, K.M. Zahidul; Sipilainen, Timo. This paper measures profit efficiency and examines the effect of access to microfinance on the performance of rice firms in Bangladesh. An extended Cobb-Douglas stochastic frontier profit function was used to assess profit efficiency and profit loss of rice farmers in Bangladesh in a survey data of 360 farms throughout the 2008-2009 growing seasons. Model diagnostics reveal that serious selection bias exists that justifies the uses of sample selection model in stochastic frontier models. After effectively correcting for selectivity bias, the mean profit efficiency of the microfinance borrowers and non-borrowers were estimated at 68% and 52% respectively, thereby suggesting that a considerable share of profits were lost due to profit inefficiencies in rice... Tipo: Conference Paper or Presentation Palavras-chave: Stochastic frontier function; Profit efficiency; Selection bias; Bangladesh; Microfinance; Agricultural Finance; Crop Production/Industries. Ano: 2011 URL: http://purl.umn.edu/116067 GROWTH OF GERMAN DAIRY FARMS UNDER THE EU MILK QUOTA AgEcon Breustedt, Gunnar; Mees, Martin. B3_3 Tipo: Conference Paper or Presentation Palavras-chave: Farm growth; Gibrat's Law; Milk quota; Selection bias; Agricultural and Food Policy; Research Methods/ Statistical Methods. Ano: 2010 URL: http://purl.umn.edu/93950 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 Interlinked Transactions in Cash Cropping Economies: The Determinants of Farmer Participation and Performance in the Zambezi River Valley of Mozambique AgEcon Benfica, Rui M.S.; Tschirley, David L.; Boughton, Duncan. This paper investigates the determinants of participation and performance of tobacco contract farmers, and the effects of participation on overall crop and household incomes in the Zambezi Valley of Mozambique. We test the existence of threshold effects in land holdings and educational attainment to identify the types of farmers that benefit. Several results stand out. First, participation in the schemes is driven by factor endowments, asset ownership and alternative income opportunities, and very little by demographic factors. Second, we find no returns to education in tobacco; this result is consistent with previous research in Mozambique but surprising in an agronomically demanding crop like tobacco. Third, there appear to be economies of scale in... Tipo: Conference Paper or Presentation Palavras-chave: Contract farming; Selection bias; Treatment effects; Threshold effects; Household income.; Crop Production/Industries; C21; D1; L1; J43; Q12. Ano: 2006 URL: http://purl.umn.edu/25244 Participation determinants and impact assessment of the Institute of Agricultural Development (INDAP) credit program Ciencia e Investigación Agraria Donoso,Guillermo; Melo,Oscar; Negrete,Eduardo. This research estimates the impact of INDAP's Credit Program on the per hectare agricultural income of small agricultural producers. To accomplish this, a Treatment Effects Model (TEM) is employed to simultaneously estímate producer incomes and program participation functions, correcting for the potential presence of selectivity bias through the correlation between the errors of both functions. The results indicate that farmers of greater age present a higher disposition to participate in the program, but their interest decreases as their age increases. Additionally, producers who are acquainted with and evaluate the financial cost of credits as well as those producers whose income comes mainly from their land, who are landowners, present a greater family... Tipo: Journal article Palavras-chave: Program impact estimation; Selection bias; Rural finance; Treatment effects model. Ano: 2010 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-16202010000200009 Registros recuperados: 11 Primeira ... 1 ... Última

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