Browsing by Author "Taylor, Daniel B."
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- Advances in Applied Econometrics: Binary Discrete Choice Models, Artificial Neural Networks, and Asymmetries in the FAST Multistage Demand SystemBergtold, Jason Scott (Virginia Tech, 2004-04-14)The dissertation examines advancements in the methods and techniques used in the field of econometrics. These advancements include: (i) a re-examination of the underlying statistical foundations of statistical models with binary dependent variables. (ii) using feed-forward backpropagation artificial neural networks for modeling dichotomous choice processes, and (iii) the estimation of unconditional demand elasticities using the flexible multistage demand system with asymmetric partitions and fixed effects across time. The first paper re-examines the underlying statistical foundations of statistical models with binary dependent variables using the probabilistic reduction approach. This re-examination leads to the development of the Bernoulli Regression Model, a family of statistical models arising from conditional Bernoulli distributions. The paper provides guidelines for specifying and estimating a Bernoulli Regression Model, as well as, methods for generating and simulating conditional binary choice processes. Finally, the Multinomial Regression Model is presented as a direct extension. The second paper empirically compares the out-of-sample predictive capabilities of artificial neural networks to binary logit and probit models. To facilitate this comparison, the statistical foundations of dichotomous choice models and feed-forward backpropagation artificial neural networks (FFBANNs) are re-evaluated. Using contingent valuation survey data, the paper shows that FFBANNs provide an alternative to the binary logit and probit models with linear index functions. Direct comparisons between the models showed that the FFBANNs performed marginally better than the logit and probit models for a number of within-sample and out-of-sample performance measures, but in the majority of cases these differences were not statistically significant. In addition, guidelines for modeling contingent valuation survey data and techniques for estimating median WTP measures using FFBANNs are examined. The third paper estimates a set of unconditional price and expenditure elasticities for 49 different processed food categories using scanner data and the flexible and symmetric translog (FAST) multistage demand system. Due to the use of panel data and the presence of heterogeneity across time, temporal fixed effects were incorporated into the model. Overall, estimated price elasticities are larger, in absolute terms, than previous estimates. The use of disaggregated product groupings, scanner data, and the estimation of unconditional elasticities likely accounts for these differences.
- Agricultural research in Senegal: Economic surplus evaluation of the adoption of variety La Fleur 11 by peanut farmersSoufi, Widad (Virginia Tech, 2001-06-04)Peanut production has been decreasing in Senegal over the past decades for historical, political, economic and environmental reasons. One of the solutions proposed by recent Senegalese administrations is to increase production through agricultural research and the development of peanut varieties that are adapted to the environmental constraints in Senegal. The last variety developed is La Fleur 11, which is very drought tolerant. The purpose of the study is to assess the economic impact of research on La Fleur 11 on the Senegalese economy through an ex-ante evaluation of the net social benefits from the adoption of this new variety. In order to fulfill this objective, an economic surplus analysis is conducted within the framework of a partial equilibrium model. Results indicate that the net social benefits from the adoption of La Fleur 11 are positive. Assuming that all peanut supply is sold to SONACOS at a producer base price and that research evaluation is conducted at the farm-level, Consumers (SONACOS) are the main beneficiaries from research. Their benefits are on average 6 times producers' (farmers). The research-induced increase in the government cost of the subsidy represents 84 percent on average of consumers' and producers' benefits; the research-induced increase in net social welfare represents 16 percent on average of consumers' and producers' benefits. The internal rate of return averages around 43 percent. When peanut markets are disaggregated, research benefits consumers (SONACOS) 3 times more than producers (farmers) at the farm level. Most of producers' benefits come from farm household consumption (47 percent of total farm-level benefits) and most of consumers' benefits come from the official seed market. At the SONACOS-level where peanut oil and cakes are exported, research benefits producers (SONACOS) only; consumers (rest of the world) do not benefit from research at this level. The IRR is more likely to be about 42 percent. This study suggests that future investments in agricultural research in Senegal can result in a positive economic impact provided that other actions are undertaken regarding extension, credit, and input distribution in order to enhance adoption and take advantage of the yield potential of the new peanut varieties. Also, this study provides a procedure of research evaluation for future use in Senegal and West Africa.
- Agricultural Technolongy in Bangladesh: a Study on Non-Farm Labor and Adoption by GenderVictoria, Melanie Villanueva (Virginia Tech, 2007-07-16)There is growing interest in learning the impacts of agricultural technologies especially in developing economies. Economic analysis may entail assessment of employment and time allocation effects of new technologies. An issue of importance in South Asia is the impacts of technological change on a specific type of occupation: rural non-farm activities. In order to fully understand these effects, the research must integrate gender differences and determine if the results would be similar irrespective of gender. This paper particularly looks at the effects of HYV adoption on time allocation and labor force participation of men and women in non-farm activities. In estimating the effects of HYV adoption on non-farm labor supply, information on the dependent variable, supply of non-farm labor (or the number of days worked while engaged in non-farm labor), is not available for individuals who do not participate in non-farm labor. Hence sample selection or self-selection of individuals occurs. A feasible approach to the problem of sample selection is the use of Heckman's Two Stage Selection Correction Model. Income functions were estimated for males and females while correcting for the sample selection of non-farm wage earners. An enhanced understanding of the conceptual links among HYV adoption, non-farm labor supply, and gender issues is achieved by discussing the Farm Household Model. The constrained maximization which is drawn from the Farm Household Model would bring about demand functions and reduced form functions for adoption and labor supply. The reduced-form equations are estimated at the individual level for the following: adoption of HYV technology in rice cultivation, and non-farm labor supply of both adult males and females. Regression results are presented for both Ordinary least squares (OLS) and Tobit estimates. HYV adoption and non-farm labor supply of men and women are influenced by several factors in Bangladesh. The household characteristics assumed to potentially determine technology adoption and non-farm labor decisions are the following: non-farm wages per month of the males and females, farm size, asset value, ratio of yield per decimal land of high-yielding to traditional variety of rice, HYV yield, local variety yield, and the ratio of variance of yield per decimal land of HYV to traditional or local varieties. The empirical findings suggest that the decision to adopt HYV technology is determined primarily by farm size, value of total assets of the household, ratio of yield per decimal of land of high-yielding to traditional variety of rice, and the ratio of variance of yield per decimal of land of high-yielding to traditional variety of rice. A larger farm size or land owned in decimal unit increases the non-farm labor supply of females, but not of men. HYV yield is significant and positive, while the local variety yield is significant and negative. This means that higher HYV yields increase the supply of non-farm labor of women, while higher local or traditional yields lower women's supply of non-farm labor.
- Analysis of Agricultural Production in Albania: Prospects for Policy ImprovementZaloshnja, Eduard X. (Virginia Tech, 1997-09-11)The overall objective of this study is to develop a framework to predict the impacts of government policies on agricultural production in Albania. The specific goal of this study is to provide some empirical estimates of the farmers' short-run supply response to government policies that effect output and input prices. Different theoretical approaches to integrating the questions this study purports to answer were considered. Two models were deemed as most appropriate for Albanian agriculture. The first is a semi-commercial farm household model and the second is the well-known indirect profit function model. The first model was preferred. However, the second was used instead, due to the lack of information necessary for an empirical application of the semi-commercial farm household model. A quadratic functional form was selected to approximate the profit function. It satisfied the Taylor series approximation convergence test. Two approaches were used to estimate the empirical model. In the first, the traditional approach, the symmetry and homogeneity conditions were imposed beforehand and then the system of equations was estimated using the ITSUR procedure in SAS. Following common practice, a joint Rao test of these conditions was conducted, implicitly assuming that the test statistic has a Fisher distribution or, stated differently, assuming that parameter estimators are normally distributed. The test results indicate that the conditions are met. A second approach, proposed by McGuirk, et al., was also used in this study. The approach proposed by McGuirk, et al., requires that, before imposing and/or testing any theoretical assumption, the unrestricted model is estimated and tested to see if all the underlying statistical assumptions of the linear regression are met. The misspecification tests suggested that the model is not statistically adequate. This finding indicated that the theoretical test conducted in the traditional approach was invalid. An alternative estimation procedure is proposed in the study for cases when a statistically adequate model cannot be specified. Named the sub-sample or the bootstrapping method, this procedure consists of randomly selecting a large number of sub-samples from the cross-sectional sample and running a regression for each of them. The large number of estimates for each of the coefficients serves as a basis for estimating 95-percent confidence intervals. An inspection of the supply and input demand elasticities calculated based on coefficients estimated through the sub-sample method revealed that half of them have wide 95 percent confidence intervals. Therefore, predicting policy impacts across all output and input equations is not possible. However, elasticities that have narrow confidence intervals and make economic sense can be used to predict isolated policy impacts, if Albania returns to the conditions that prevailed before the political turmoil of 1997.
- Analysis of Policies Affecting Pesticide Use in EcuadorYamagiwa, Takayoshi Jose II (Virginia Tech, 1998-02-05)Nominal Rates of Protection (NPR) were calculated to quantify the degree of pesticide subsidy in Ecuador from 1991 to 1996. Equilibrium exchange rates were computed first to determine the indirect and total NPR's in addition to the direct NPR's. The computed equilibrium exchange rates from 1987 to 1996 indicated a decreasing trend in Sucre overvaluation. The direct NPR's indicated a small tax on pesticides due to a tariff and customs tax, and the indirect NPR's indicated a decreasing trend of subsidization due to the reduction in Sucre overvaluation. In sum, total NPR's indicated that the subsidy on pesticides has decreased substantially. A demand function for pesticides was estimated to quantify the effect of price distortions on pesticide demand. Due to the limited degrees of freedom, a statistically significant function was not obtained. However, pesticide price, agricultural credit, and overvaluation of the Sucre were statistically significant in influencing pesticide demand. Policy implications were drawn based on empirical results and background information. Since the agricultural profitability of small farms producing outputs for domestic consumption is most affected by the current economic liberalization, the Ecuadoran government may need to find a means for supporting the profitability of these farms to protect national agricultural productivity. Policies that aid these farmers in the adoption of inexpensive integrated pest management (IPM) technologies would help achieve this end, while reducing the environmental and health problems caused by pesticide use.
- An analysis of the relationship between sectoral activity, diversification, and structural change in the economyBasu, Rathin (Virginia Tech, 1990-04-03)The purpose of this study is to analyse the changes, if any, that take place in regional economic structures in the process of diversification, and the roles of sectors in such changes. Input-Output and Structural Path Analysis are used to develop indices that may be used for carrying out the analysis of these issues. A method is also developed for examining the role of linkages with respect to the fundamental structure of production outlined by Simpson and Tsukui. Using these indices and methods, the economic relationships between sectors and the economic structures of six planning districts in Virginia, in addition to the economies of the state of Virginia and the U.S. are analysed and compared. On the basis of these analyses, it is concluded that: (a) The feature of bloc independence found at the level of first order transactions in an economy is diluted at the level of higher order transactions in the metals bloc. However it persists strongly at higher levels of transactions in the nonmetals bloc. (b) The sectors of the metals, nonmetals and services blocs show a proportionate development of linkages irrespective of the degree of diversification of the economy. (c) Contrary to Hirschman's suggestion that complexity of linkages increases with diversification, the results suggest that diversification leads to less complexity in the linkage relationships. (d) The linkages of the agricultural sectors in Virginia are biased towards the services sectors. In the case of the agricultural sectors at the national level, the linkages are biased primarily towards the manufacturing sectors. The implications of these findings for development policy are discussed.
- Analysis of timber harvest scheduling under alternative levels of land aggregation: an application to a hypothetical Mexican forest ownershipHernandez-Vazquez, Edgardo (Virginia Polytechnic Institute and State University, 1989)The problem of optimal land organization was approached via a general methodology to aggregate finely distinguished planning unit areas of an even-aged ponderosa pine forest in Northwestern Mexico. Factor analysis was applied to eighteen timber inventory variables to produce four independent and meaningful constructs that explained 87% of the total variable set’s variation. Next, each planning unit area was characterized by its factor scores and an Euclidean-metric based analysis was applied. The resultant Dendrograrn’s structure helped to define four levels of land aggregation that were evaluated with the same forest management policy. This policy simulated current Mexican forestry guidelines such as replacement stand’s regimes based on maximum mean annual increment, and area volume constraints for timber harvest scheduling. Then, the present value-maximizing timber harvest schedules for each level of land organization was found by using LP Model 1 formulations. Results showed that timber harvesting net benefits varied between 1.3% and 7.0% across levels of land aggregation. This fact was a consequence of the biophysical homogeneity of the forest and the Mexican assumptions of prices and flat costs for overhead and planning. Theoretical considerations indicated that if overhead and planning costs are properly considered for every level of land aggregation, the study’s methodology could show a greater present value difference between alternative levels of land organization.
- An analytic model of the food consumption behavior of health-conscious individualsKambhampaty, S. Murthy (Virginia Tech, 1994-05-05)Evidence of changing patterns of food consumption behavior is presented. Previous attempts at explaining these changes are critically reviewed and the need for an alternate approach is identified. A model of consumer behavior in which utility from food consumption is maximized subject to outlay for foods and limits on the consumption of fat, cholesterol, sodium, and/or other food components is proposed. This model yields a system of demands that are functions of prices and outlay as well as the composition of food and limits on the consumption of these components. The structure of this model is examined and restrictions on consumer food demands are derived. The derivation of individual demands based on the proposed model is demonstrated using a specific indirect utility function. Tests of the joint hypotheses that fat or cholesterol consumption determines food demand are defined. The computation of aggregate food demand elasticities with respect to changes in prices and changes in attributes such as fat or cholesterol consumption is demonstrated. Data necessary for estimating the parameters of the model and testing hypotheses are identified. The model proposed in this study allows tests of the hypothesis that food demands are not affected by food composition as well as measurement of these effects
- Analyzing the Economic and Environmental Impacts of Agricultural Alternatives - the Case of Virginia's Eastern ShoreKalo, Altin A. Jr. (Virginia Tech, 1997-12-03)The evaluation of production alternatives in agriculture requires a close examination of their economic and environmental impacts. This study was conducted to identify the crops with the highest profit potential given terminal market prices over the last five years, evaluate the feasibility of adopting new crop alternatives, given historical price information and limited production resources, and determine the potential environmental impacts of adopting new cropping strategies in Accomack and Northampton Counties on the Eastern Shore of Virginia. A database of daily terminal price information was created to identify the market windows for specific commodities, their respective high, median and low prices, and their price variability over the last five years. A linear programming model was used to determine optimal farming operations for those farmers that grow only wheat and soybean versus farmers who are willing and able to include vegetables in their crop mix. PLANETOR, an environmental impact computer program, was used to estimate the potential soil erosion, pesticide leaching and runoff, nitrogen leaching, and phosphorous runoff for different scenarios. The model shows that some of the new vegetable commodities could substantially increase the net returns of the farming operations in question. Romaine and Boston Lettuce were consistently selected as the most profitable alternatives while the region's traditional crops offered little competition. Wheat and soybean production showed acceptable levels of soil erosion, as defined by the T-values for the region, and low potential for nitrogen leaching. They did, however, exhibit a higher potential for water contamination, through leaching, or runoff, of high toxicity chemicals. Although lettuce production had higher than recommended soil losses, a well-diversified crop mix offsets its negative impacts at the farm level. Lettuce also uses low toxicity chemicals, decreasing potential health hazard from their leaching or runoff. The introduction of the new vegetable commodities is recommended on the basis of the high profits that they offer, as well as the more positive pesticide leaching and runoff potential. Their final adoption, however, should take place only after establishing a well defined marketing strategy and resolving potential marketing problems. No crop exists that could offer both high profits and have no impact on the environment. Kenaf was thought to be one, but it was soon eliminated on both grounds. This study showed, however, that the new vegetable crops considered may offer better net returns, while they do not necessarily translate into environmental disasters.
- Assessing Factors Affecting Adoption of Agricultural Technologies: The Case of Integrated Pest Management (IPM) in Kumi District, Eastern UgandaBonabana-Wabbi, Jackline (Virginia Tech, 2002-11-18)Improper pesticide use on crops causes adverse effects on humans, livestock, crops and the environment. Integrated pest management practices emphasize minimal use of pesticides in controlling pests, and their adoption by farmers can reduce the use of pesticides and their adverse impacts. The introduction of IPM CRSP activities in Uganda to institutionalize IPM methods focused on priority crops in the country. This study analyzed adoption of eight IPM technologies on cowpea, sorghum and groundnuts. Low levels of adoption (<25%) were found with five of these technologies while three technologies had high adoption levels (>75%). Results indicate that farmers' participation in on-farm trial demonstrations, accessing agricultural knowledge through researchers, and prior participation in pest training were associated with increased adoption of most IPM practices. Size of farmer's land holdings did not affect IPM adoption suggesting that IPM technologies are mostly scale neutral, implying that IPM dissemination may take place regardless of farmer's scale of operation. Farmers' perception of harmful effects of chemicals did not influence farmers' decisions in regard to IPM technology adoption despite their high knowledge of this issue, suggesting that these farmers did not consider environmental and health impacts important factors when choosing farming practices. Farmers' managerial capabilities were not important in explaining cowpea IPM technology adoption.
- Assessing Farm-Level and Aggregate Economic Impacts of Olive Integrated Pest Management Programs in Albania: an Ex-Ante AnalysisDaku, Lefter S. (Virginia Tech, 2002-04-11)Concerns about the harmful effects of pesticides on the environment, human health, and wildlife have led to research and promotion of integrated pest management (IPM) strategies. Recently, an IPM program was introduced in the Albanian olive sector through the USAID-funded global IPM-CRSP project to develop improved olive IPM technologies. This study develops and applies a protocol for integrated economic impact assessment of olive pest management strategies designed by the IPM-CRSP project in Albania. The main components of the integrated approach for economic impact assessment of olive IPM include (i) net return analysis for measuring farm level impacts; (ii) economic surplus modeling for measuring market-level impacts; and (iii) modeling of IPM adoption under output uncertainty. The economic surplus equilibrium displacement model developed for the Albanian olive market with no international trade accounts for IPM research-induced supply shifts, increased demand due to quality improvement, and research-induced spillovers to non-target zones. The main sources of data for performing partial budgeting and economic surplus analysis were: (i) an expert survey; (ii) partial budgets compiled based on a farmer survey and expenditure records from field-level experiments; and (iii) data collected at the market level. The data used to estimate the dichotomous logit model came from a 1999 survey of 200 growers and a survey of 120 growers carried out in 2000 in the Vlora district of Albania. The net return analysis indicates that compared to conventional practices, the proposed olive IPM packages generally promise higher yields, improved quality of olive products, lower pesticide use, and higher net returns to producers. However, adoption of some of the IPM practices implied higher production costs. Based on the simulation results, the Albanian olive industry has the potential to derive a net IPM research benefit between $39 million (assuming that farmers move directly from minimum spraying to IPM) and $52 million (assuming that farmers move from full pesticide program to IPM) over the next 30 years. Farmers' reliance on pesticide use on olives and other crops does not seem to hinder IPM adoption. Grower perceptions and the process of expectation formation significantly influence adoption decisions. Addressing the process of expectation formation and changing these perceptions by educational programs and better access to information will encourage IPM adoption.
- Assessing the feasibility and potential expansion of large-scale riparian irrigation in VirginiaTaylor, Daniel B.; Ross, Burton Blake; Vellidis, G.; Lanier, Alan B. (Virginia Water Resources Research Center, Virginia Polytechnic Institute and State University, 1985-09)The purpose of this study was to develop a method, using readily available information, for evaluating the feasibility of t he expansion of large scale riparian based irrigation. This report represents the first in a series of reports addressing this issue. Its primary purpose is to document the methods which were employed in the feasibility analysis. Microcomputer irrigation system design models were developed to calculate the annual costs of installing and operating center pivot, traveling gun, big gun, and portable pipe irrigation systems. The information generated by these design models was summarized by estimating a series of equations using ordinary least squares regression techniques. These equations can be employed by planners and policy makers in Virginia to evaluate the potential of future conflicts in riparian water use arising from irrigation. An example using the equations in a benefit-cost analysis was presented for Havover County where it borders the Pamunkey River. It was recommended that this procedure be further refined to increase its flexibility , that data bases be developed for the areas of potential riparian based irrigation, and that the entire evaluation procedure be computerized and made more user friendly to facilitate its use by water use policy makers and planners.
- Assessment of policies and socio-economic factors affecting pesticide use in the PhilippinesTjornhom, Jessica D. (Virginia Tech, 1995)A logit model was employed to determine the relative importance of socioeconomic factors influencing the misuse of pesticides on vegetables in Central Luzon, Philippines. The analysis revealed an increase in pesticide misuse associated with the following factors: a high value placed on advice from a chemical company representative; membership in a cooperative, village or farmers' association; and visits by a Department of Agriculture technician to discuss non-pesticide means of controlling vegetable pests. Those factors which reduced pesticide misuse included: increased age and educational attainment; access to integrated pest management training through the Farmer Field School; receiving credit from a cooperative; and agreement with the perception that killing natural enemies could hasten pest infestation. The effective rate of protection on nine pesticides was calculated to quantify the net effects of pricing and exchange rate policies on the degree of subsidy or tax experienced by pesticide importers. It was found that the effective rate of protection for the nine pesticides was between negative 12 and 25 percent when the exchange rate effects were accounted for. However, the rate of protection became more negative when the equilibrium exchange rate was used indicating that exchange rate overvaluation offset the tax pesticide importers face. In addition, the analysis indicated that pricing and exchange rate policies have created a six to eight percent subsidy on pesticide prices for the years 1989 to 1993. This subsidy on pesticides has increased both consumer and producers welfare and the quantity of pesticides used in the Philippines.
- Balancing competing development objectives in the Trifinio region of Central America: economic and social development and environmental protectionElias, Carlos Guillermo (Virginia Tech, 2008-08-04)This dissertation contains three related papers. The first paper revisits the concept of integrated rural development and provides examples on how to design balanced development work programs for the Trifinio region, a small rural region shared by 3 Central American countries. Work programs should balance 3 development objectives: economic development, social development and environmental protection. Finding a balance between these 3 competing objectives is difficult. The literature of Sustainable Development recognizes that policy makers often fail to balance objectives while the Integrated Rural Development literature points out the challenges of combining the objectives in a manageable project. We argue that, by focusing on identifying sources of economic friction and by accurately measuring tradeoffs using appropriate tools, we can design sound work programs. We present a toolkit that allows policy makers to identify sources of economic friction, measure their drag on the economy, and prioritize these sources so as to reduce the frictions that slow rural development. The toolkit contains 4 tools to assist in program design and 1 for implementation. GIS and building municipal indices of outcomes, household surveys, conjoint analysis and economic field experiments, are the tools that we have applied to design work programs in the Trifinio. In addition, balanced programs must be multi-dimensional in scope so we propose a tool that focuses on the institutional setup required for successful program execution. Finally we make policy recommendations and suggest additional tools that may also be added to our tool kit. In the second paper we create municipal indices of agricultural value of production, personal consumption and poverty in the Trifinio region of Central America with the objective of using them to guide investment priorities. Our indices synthesize information from the complex economic, social and geographic system of this region. In this respect we depart from established practices of estimating indices—for outcomes such as competitiveness—that select factors and create the index by adding them up. The established practice follows a normative approach because the index results from adding factors that should have an impact on the outcome. In this context the index author does not observe the outcome or the impact of factors; and does not know the functional relationship between factors and outcome. The author assumes all the information to create indices. Our methodology follows a positive approach and departs from the established practice because we estimate the outcome and identify factors that have an impact on it. To do it we use household survey and municipal level data to estimate determinants of agricultural value of production, consumption and poverty for the 45 municipalities in the Trifinio region. We then show how to identify municipalities in greatest need, identify factors of greatest impact on the outcome, and identify complementary activities. In addition we use GIS to develop a method that allows for the "generation" of missing agricultural-related data by extrapolating high quality yet limited information from a subsection of the region to the whole. The data generated has been validated in the field by agriculture experts thus confirming the legitimacy of this innovation. Finally we offer policy recommendations. The final paper presents an economic model of group formation with an application to data collected from an agricultural credit program in western Honduras. We formulate a simple theory of group formation using the concept of centers of gravity to explain why individuals join a group. According to our theory, prospective members join based on the potential benefits and costs of group membership, and based on their perception of social distance between themselves and other group members. Social distance is unobservable by outsiders but known by the individual: if you are in then you know who has blue hair. Thus, we argue that social distance helps explain preferences for group formation. To test our theory we analyze data collected from members and non-members of PRODERT, a program that has helped create 188 "Cajas Rurales" (CRs). Using conjoint analysis we test for differences in preferences between members and non-members for the main attributes of the CR. We find that members and non-members exhibit similar preferences for the attributes of the CR; therefore non-membership is not related to supply factors. Using information gathered by executing field experiments, we estimate a proxy for social distance. We use this proxy to run a group formation equation and find that it explains, along with individual characteristics, participation in the CR. Finally we offer suggestions on how to balance performance and coverage in programs in which beneficiaries decide who joins. Small cohesive groups may show exceptional performance at the cost of low coverage, and the opposite may be true.
- A Bio-Economic Model of Long-Run Striga Control with an Application to Subsistence Farming in MaliMullen, Jeffrey D. (Virginia Tech, 2000-07-10)The parasitic weeds belonging to the genus Striga are among the world's most tenacious, prolific and destructive agricultural pests. Crop loss estimates due to Striga infestations can reach 100 percent. Furthermore, the weeds' affinity for low-fertility soils and low rainfall means that those farming the most marginal lands are most severely affected. Nonetheless, subsistence farmer have yet to adopt seemingly beneficial control practices to any appreciable degree. This paper develops a bio-economic model capable of identifying: (1) affordable, effective Striga control practices consistent with the resource constraints of subsistence farmers; and (2) barriers to the adoption of those practices. The model is comprised of two components: a biological component modeling Striga population dynamics, and an economic component representing the production opportunity set, resource constraints, and price parameters farmers face. The model is applied to two zones in Northwestern Mali, Sirakorola and Mourdiah, and solved using non-linear, dynamic programming. Data collected by the USAID IPM-CRSP/Mali project are used to specify the economic parameters of the model. A new technique for estimating the lower bound of a farmer's production planning horizon is also developed and employed in the application of the model to Sirakorola and Mourdiah. The results of several model scenarios indicate that the availability of information regarding the efficacy of Striga control practices is a primary barrier to their adoption by subsistence farmers. The movement of Striga seed between fields, however, is of limited importance. The "optimal control practices" identified by the model depend on the size and demographic composition of the production unit (UP), the zone in which the UP is located, and the cash budget available to the UP. At low budget levels, the model suggests planting millet without fertilizer at a high density in Sirakorola and a low density in Mourdiah. At high budget levels, the model suggests planting millet at a high density in both zones while applying urea. The benefits of adopting the optimal set of practices are presented in both nutritional and financial terms, and can reach as much as a ten-fold increase in the nutritional content of and financial returns to a harvest.
- Biotechnologies in the Philippines: The Cost of RegulationBayer, Jessica Christine (Virginia Tech, 2007-04-20)Biotechnologies potentially have significant benefits for developing countries but many countries lack complete regulatory processes to allow their release. In evaluating the potential benefits of genetically modified crops, one must be able to measure the true cost of regulations in addition to the other costs associated with bringing the crop to market. The objectives of this paper are to (1) identify the direct costs of the regulation of Bt eggplant, Bt rice, ringspot virus resistant (PRSV) papaya and virus resistant tomatoes in the Philippines, and (2) estimate the opportunity cost of time lost in the regulatory process. The study compares the cost of regulations as they differ by factors such as the existence of previous studies on the product or the intention for export or domestic use. It is hypothesized that the costs are greater for products that are intended for export or human consumption or are produced by the private sector. It is also hypothesized that these factors increase the time to complete the regulatory process, therefore increasing the opportunity cost of time. This study evaluates the economic impact of the GMO regulatory process on the change in producer surplus, the net present value and the internal rate return using an economic surplus model. Scientists and other experts in the field of GMOs and regulation were interviewed to obtain the necessary data on the regulatory process. The evaluation was carried out for four different commodities in the Philippines, Bt Rice, Bt Eggplant, PRSV Papaya and MVR Tomato. The results for the open economy model revealed a change in producer surplus, as a result of the GMO research, of $418.3 million for Bt Rice and $353.7 million for PRSV Papaya. The closed economy model of Bt Eggplant has a change in producer surplus of $25.1 million and a change in total surplus of $40.8 million while the result for the change in producer surplus for MVR Tomato is $19.3 million and the change in total surplus is $51.6 million. A sensitivity analysis of the results was then carried out in which the elasticity of supply, the cost of regulation, and the release date were each varied in order to show the welfare impact of such changes. The sensitivity analysis revealed limited changes in surplus when elasticity and regulatory costs were changed. However, changing the date of release or commercialization resulted in monumental changes in surplus.
- Bridging the Information Gap with Cost-Effective Dissemination Strategies: The Case of Integrated Pest Management in BangladeshHarris, Leah M.; Norton, George W.; Rezaul Karim, A.N.M.; Alwang, Jeffrey R.; Taylor, Daniel B. (Southern Agricultural Economics Association, 2013)Cost-effective extension strategies are needed to promote widespread adoption of agricultural technologies in developing countries. Integrated pest management (IPM) practices, for example, can offer economic, health, and environmental benefits but remain largely underused. This study evaluates the current IPM dissemination program implemented by the Bangladesh Department of Agricultural Extension and uses a linear programming model to examine alternative strategies to improve IPM adoption. Results suggest that technology transfer programs may increase their impact by reallocating funding from intensive but costly interpersonal communication methods (i.e., farmer field schools) to less intensive methods (i.e., mass media and field days) that reach broader audiences.
- Bridging the Rural - Urban Digital Divide in Residential Internet AccessWhitacre, Brian E. (Virginia Tech, 2005-09-01)This dissertation explores the persistent gap between rural and urban areas in the percentage of households that access the Internet at home (a discrepancy commonly known as the "digital divide"). The theoretical framework underlying a household's Internet adoption decision is examined, with emphasis on the roles that household characteristics, network externalities, and digital communication technology (DCT) infrastructure potentially play. This framework is transferred into a statistical model of household Internet access, where non-linear decomposition techniques are employed to estimate the contributions of these variables to the digital divide in a given year. Differences in Internet access rates between years are also analyzed to understand the importance of temporal resistance to the continuing digital divide. The increasing prevalence of "high-speed" or broadband access is also taken into account by modeling a decision process where households that choose to have Internet access must decide between dial-up and high-speed access. This nested process is also decomposed in order to estimate the contributions of household characteristics, network externalities, DCT infrastructure, and temporal resistance to the high-speed digital divide. The results suggest that public policies designed to alleviate digital divides in both general and high-speed access should focus more on the broader income and education inequities between rural and urban areas. The results also imply that the current policy environment of encouraging DCT infrastructure investment in rural areas may not be the most effective way to close the digital divide in both general and high-speed Internet access.
- Capital Access in Rural VirginiaKruja, Zana (Virginia Tech, 1997-07-01)The objective of this study is to determine whether there are inadequacies in the rural financial markets of Virginia. The analysis is based on data from a survey of farm and non-farm small businesses, in five rural counties in Virginia. A Probit model is used to determine whether the financing difficulty encountered by small rural businesses is significantly determined by non-risk characteristics of users of capital and/or non-risk characteristics of local capital markets. Four variables representing different aspects of financing difficulty are used as the dependent variables in each of the four models used in this study. These variables are, loan denial and non-local financing reported by the survey respondents, opinions of survey respondents on the adequacy of local capital markets, and their expectations on future satisfaction with the performance of the local capital market. Businesses' risk characteristics should be the only determinant of the financing difficulty faced by capital users. However, this analysis indicates that access to capital is determined by non-risk local businesses' and local financial market characteristics as well. Among the most influential non-risk characteristics are: firm size, number of non-local locations, number of competitors in the local market, form of ownership, size of local financial institutions, and local financial institutions' specialization in lending to small businesses. In addition there are large differences in the way financing needs are met in different economic sectors in rural areas. Non-agricultural businesses seem to have less access to financing compared to agricultural businesses. Further, there is evidence that information in rural financial markets is not complete, and that the sources of information are limited. The evidence on availability of capital is mixed and insufficient to conclude that this is an issue in rural Virginia. The results of the analysis are used to identify ways to increase the availability of cost efficient capital for new and small businesses in rural areas in Virginia. The recommendations include considerations on how to improve governmental presence in rural capital markets to provide or facilitate better access to capital.
- A case study of investment in agricultural sustainability: adoption and policy issues for nitrogen pollution control in the Chesapeake Bay drainageNorris, Patricia E. (Virginia Polytechnic Institute and State University, 1988)Nutrient loadings to the Chesapeake Bay are a source of concern for water quality agencies. In particular, excess nitrogen loadings from agricultural production activities threaten water quality in the Bay. Questions have been raised about how effectively traditional BMPs can control nitrogen loss from crop production. This study examines agricultural nitrogen pollution control from an input management perspective. Using an economic and physical model, seven production systems and nitrogen management strategies are compared in terms of input use, profitability, and nitrogen loss potential. Results suggest that several of the production systems will reduce residual nitrogen without reducing profits. However, it is recognized that factors in addition to profitability will influence producers' nitrogen management decisions. Therefore, using the results of a farmer survey, adoption models are estimated to examine the impact of production system characteristics and producer characteristics on the decision to use an alternative production system and nitrogen management strategy. Finally, a sensitivity analysis is conducted to examine the impact of alternative policy tools on adoption incentives. Both financial incentives and education and information programs are found to be important tools for influencing producers' decisions. Producers' interest in the alternative systems and desire for information on the systems suggest that agricultural research will contribute by assuring that producers have access to adequate information on the alternative systems.