Esta tese é composta por três ensaios sobre Economia do Empreendedorismo. O primeiro deles trata sobre os determinantes do empreendedorismo no Brasil a partir de modelos de escolha ocupacional, usando os microdados da Pesquisa Nacional por Amostra por Domicílios (PNAD) do ano de 2012. A estratégia empírica adotada empregou os modelos de escolha discreta na estimação da escolha ocupacional. Os resultados demonstraram que existem efeitos significativos para as variáveis: anos de estudos iniciais, sexo, estado civil assim como pensionista e aposentado. Para completar a análise foram estimadas as equações de rendimento, as quais explicam a escolha pela ocupação empreendedora em função dos ganhos relativos ao trabalho assalariado. Já o segundo ensaio tem como objetivo apresentar uma evidência empírica para a relação existente entre empreendedorismo e corrupção nos estados brasileiros, utilizando uma abordagem teórica e empírica. Este artigo utiliza um indicador objetivo de corrupção governamental estadual baseado no Cadastro de Contas Irregulares do Tribunal de Contas da União (CADIRREG) como proxy para a corrupção regional e a abertura de novas empresas per capita como medida para a atividade empreendedora. Foram utilizados o método de dados de painel estático, dinâmico e o método GMMSYS, estes últimos empregados para corrigir possíveis problemas de endogeneidade. Os resultados encontrados mostraram-se coerentes com a hipótese teórica “grease in the wheels”, na qual a corrupção influencia positivamente a atividade empreendedora em países em desenvolvimento com elevada burocracia. Por fim, o terceiro ensaio avalia os impactos do empreendedorismo via inovação a partir do Global Trade Analysis Project – GTAP, um modelo de equilíbrio geral computável (EGC), destacando os impactos no crescimento econômicoe no bem-estar geral da economia. Os resultados mostraram-se coerentes com a literatura da Economia do Empreendedorismo, mostrando que aumento no empreendedorismo conduz a uma elevação no crescimento econômico e bem-estar. / This thesis consists of three essays on the Economics Entrepreneurship. The first deals with the determinants of entrepreneurship in Brazil from occupational choice models, using the data from the National Household Sample Survey (PNAD) of 2012. The empirical strategy adopted has employed discrete choice models in the estimation of occupational choice. The results showed that there are significant effects on the variables: years of initial studies, gender, marital status as well as pensioners and retired. To complete the analysis were estimated earnings equations, which explains the choice by the entrepreneurial occupation in terms of earnings for paid employment. The second test aims to present empirical evidence for the relationship between entrepreneurship and corruption in the Brazilian states, using a theoretical and empirical approach. This article uses an objective indicator of state government corruption based on the Register of Irregular accounts of the Court of Audit (CADIRREG) as a proxy for regional corruption and the opening of new companies per capita as a measure for regional entrepreneurial activity. They used the method of static panel data, dynamic and GMM-SYS method to correct the endogeneity problem. The results proved to be consistent with the theoretical hypothesis "grease in the wheels" in which corruption positively influence the entrepreneurial activity in developing countries with high bureaucracy. Finally, the third test evaluates the impacts of entrepreneurship via innovation from the Global Trade Analysis Project - GTAP, a model of computable general equilibrium (CGE), highlighting the impacts on economic growth and overall well-being economy. The results were consistent with the literatureof Entrepreneurship Economics, showing that increased entrepreneurship leads to a rise in economic growth and well-being.

Esta dissertação visa avaliar o padrão comportamental dos pedestres nos deslocamentos na cidade de Porto Alegre. É abordado a partir da base de dados provenientes da pesquisa de entrevistas domiciliares realizadas em 2003 em Porto Alegre. Para isto, caracterizaram-se os deslocamentos a pé na cidade e identificaram-se as regiões de maior e menor concentração de viagens a pé. A fim de determinar os fatores que influenciam a decisão de caminhar foram estimados modelos logit binomiais para as viagens menores que 2 km em cada uma das regiões identificadas anteriormente. As variáveis explicativas para os modelos analisados incluem características do domicílio (disponibilidade de automóvel e renda por domicílio), dos residentes (idade), das viagens (distância e motivo da viagem), da forma urbana (densidade de domicílios, densidade populacional, comprimento médio das quadras, padrão do sistema viário, tipo de uso do solo e estacionamento tarifado em área pública) e da disponibilidade de transporte coletivo na origem da viagem. Foram consideradas duas categorias de viagens: viagens por motivo trabalho/estudo e viagens por motivo não trabalho/estudo (motivos recreacionais, compras, saúde, assuntos pessoais e outros). Os resultados do estudo mostram que características sócio-econômicas dos residentes, características das viagens e da forma urbana influenciam a escolha do modo a pé. Analisando os valores de elasticidade obtidos para as duas categorias de viagens originadas em Petrópolis e no Centro pode-se inferir que as variáveis que exercem maior influência estão relacionadas principalmente a características da viagem (distância) e à configuração física da rede viária. A análise de sensibilidade evidenciou a sensibilidade do modelo frente a alterações das variáveis estudadas. Os resultados obtidos servem de apoio para um planejamento mais adequado da mobilidade e acessibilidade dos pedestres. / This thesis aims to evaluate the pedestrians’ behavior in Porto Alegre. The study was based on a Porto Alegre household survey of 2003. During the analysis, the pedestrian trips were characterized and the traffic zones with the larger and the smaller number of pedestrian trips were identified. In order to determine the influencing factors related to the walk choice, binomial logit models were developed for trips with less than 2km in each traffic zone previously identified. The explanatory variable used in the models included the characteristics of the household (auto availability and household income), of the household members (age), of the trip (distance and purpose of the trip), of the built environment (housing units density, population density, mean block size, street patterns, land use and public parking), and transit availability in the origin of the trip. Two types of pedestrian travel were considered: work and non-work trips (shopping, health, personal purposes and others). The study results showed that socio-economic characteristics, trip characteristics and local measures of the built environment influence walk modechoice. Elasticity results for the two types of trips, with origin in “Petrópolis” and Downtown, indicate that the most influence variables are connected with trip characteristics (distance) and street design. The sensibility analysis showed the model sensibility strength under the changes introduced in the variables studied. These analysis results may provide support for a better planning for pedestrians’ mobility and accessibility.

Esta tese é composta por três ensaios sobre Economia do Empreendedorismo. O primeiro deles trata sobre os determinantes do empreendedorismo no Brasil a partir de modelos de escolha ocupacional, usando os microdados da Pesquisa Nacional por Amostra por Domicílios (PNAD) do ano de 2012. A estratégia empírica adotada empregou os modelos de escolha discreta na estimação da escolha ocupacional. Os resultados demonstraram que existem efeitos significativos para as variáveis: anos de estudos iniciais, sexo, estado civil assim como pensionista e aposentado. Para completar a análise foram estimadas as equações de rendimento, as quais explicam a escolha pela ocupação empreendedora em função dos ganhos relativos ao trabalho assalariado. Já o segundo ensaio tem como objetivo apresentar uma evidência empírica para a relação existente entre empreendedorismo e corrupção nos estados brasileiros, utilizando uma abordagem teórica e empírica. Este artigo utiliza um indicador objetivo de corrupção governamental estadual baseado no Cadastro de Contas Irregulares do Tribunal de Contas da União (CADIRREG) como proxy para a corrupção regional e a abertura de novas empresas per capita como medida para a atividade empreendedora. Foram utilizados o método de dados de painel estático, dinâmico e o método GMMSYS, estes últimos empregados para corrigir possíveis problemas de endogeneidade. Os resultados encontrados mostraram-se coerentes com a hipótese teórica “grease in the wheels”, na qual a corrupção influencia positivamente a atividade empreendedora em países em desenvolvimento com elevada burocracia. Por fim, o terceiro ensaio avalia os impactos do empreendedorismo via inovação a partir do Global Trade Analysis Project – GTAP, um modelo de equilíbrio geral computável (EGC), destacando os impactos no crescimento econômicoe no bem-estar geral da economia. Os resultados mostraram-se coerentes com a literatura da Economia do Empreendedorismo, mostrando que aumento no empreendedorismo conduz a uma elevação no crescimento econômico e bem-estar. / This thesis consists of three essays on the Economics Entrepreneurship. The first deals with the determinants of entrepreneurship in Brazil from occupational choice models, using the data from the National Household Sample Survey (PNAD) of 2012. The empirical strategy adopted has employed discrete choice models in the estimation of occupational choice. The results showed that there are significant effects on the variables: years of initial studies, gender, marital status as well as pensioners and retired. To complete the analysis were estimated earnings equations, which explains the choice by the entrepreneurial occupation in terms of earnings for paid employment. The second test aims to present empirical evidence for the relationship between entrepreneurship and corruption in the Brazilian states, using a theoretical and empirical approach. This article uses an objective indicator of state government corruption based on the Register of Irregular accounts of the Court of Audit (CADIRREG) as a proxy for regional corruption and the opening of new companies per capita as a measure for regional entrepreneurial activity. They used the method of static panel data, dynamic and GMM-SYS method to correct the endogeneity problem. The results proved to be consistent with the theoretical hypothesis "grease in the wheels" in which corruption positively influence the entrepreneurial activity in developing countries with high bureaucracy. Finally, the third test evaluates the impacts of entrepreneurship via innovation from the Global Trade Analysis Project - GTAP, a model of computable general equilibrium (CGE), highlighting the impacts on economic growth and overall well-being economy. The results were consistent with the literatureof Entrepreneurship Economics, showing that increased entrepreneurship leads to a rise in economic growth and well-being.

O estímulo aos modos ativos de viagem através de modificações na forma urbana - infraestrutura, edificações e atividades - é objeto do planejamento das cidades contemporâneas desde que os problemas do transporte motorizado se revelaram críticos e contrários à ideia de sustentabilidade urbana. Congestionamentos, poluição, custos monetários e sociais elevados estão associados ao modelo de urbanização e mobilidade da maioria das cidades, especialmente nos países em desenvolvimento, onde a explosão da frota motorizada é concomitante à aceleração dos processos de urbanização e espalhamento urbano. Mais recentemente, a revelação de relações de causalidade entre o excesso de utilização dos veículos particulares e problemas de saúde crônica das populações urbanas levou a um crescimento das pesquisas e iniciativas de estímulo às caminhadas como modo de transporte. Também o interesse pela qualidade da experiência da vida na cidade veio somar-se a este corpo de conhecimento, trazendo as ideias de vitalidade urbana e urbanidade para junto dos estudos de caminhabilidade. O interesse extrapolou a análise de demanda agregada que visa o incremento do modo a pé e passou a dar atenção aos caminhos pelos quais as pessoas se movimentam, conectando origens e destinos nos interior das cidades. Este trabalho procura avançar neste aspecto ao propor um método de avaliação dos atributos da forma urbana baseado no monitoramento de caminhantes com dispositivos de posicionamento global (GPS) e modelos de escolha discreta. Um estudo na cidade de Porto Alegre acompanhou indivíduos durante os anos de 2011 a 2014 e, através da representação de diversos atributos urbanos em ambiente SIG, associou as trajetórias realizadas com as características da forma da cidade, concluindo que elas influenciam a utilidade percebida das alternativas de caminho e, portanto, atuam sobre o processo decisório dos pedestres. Para além da simples distância ou declividade, outras características como o tamanho dos trechos, a hierarquia das vias, a presença de prédios marcantes e espaços abertos e a densidade de edificações ao longo dos eixos revelaram-se influentes neste processo. Poucas intersecções e cruzamentos, predomínio de vias amigáveis ao pedestre e edificações arranjadas de forma menos densa são alguns dos atributos que apresentaram maior relevância para a decisão de “por onde ir” no âmbito deste estudo. A amostra relativamente pequena e a concentração das viagens no entorno do Parque Farroupilha e do campus da UFRGS não permitem generalizar os resultados. Porém, o estudo pode ser considerado válido enquanto exploração, pois constrói uma metodologia que pode ser ampliada e aplicada em outros contextos. Além disso, os resultados revelam particularidades da realidade local que parecem indicar a existência de diferenças comportamentais significativas em relação às cidades do primeiro mundo, tornando-o promissor como instrumento de suporte a políticas e projetos de mobilidade urbana sustentável no Brasil. / Since motorized transport problems have proved to be critical and contrary to the concept of urban sustainability, the idea of increasing the active travel modes through changes in urban form is a key subject of today´s mobility agenda. Traffic congestion, air pollution and severe monetary and social costs are associated with the current patterns of urbanization and mobility, especially in developing countries, where an explosive motorized fleet growth occurs simultaneously to an acceleration of urbanization and sprawl processes. Most recently evidences of a causal relationship between massive use of private vehicles and chronic health disorders have led to an increase in research about walking as an effective and clean mode of transportation. Also, the interest about the quality of life experience in the city came to add up to this body of knowledge, bringing in ideas of livability to walkability studies. Beyond the aggregate demand studies that aim to increase the walking mode share, there is now a growing interest on more localized aspects of the walking phenomenon - the routes - trying to understand the ways in which people travel on foot when connecting origins and destinations. This work proposes a method based on assessing data from actually taken walking trips using GPS devices and on modeling pedestrian´s choice behavior using discrete choice models. A study in the city of Porto Alegre, south of Brazil, followed 82 individuals for three consecutive days and, through the representation of several layers of urban data in a GIS environment, associated their trajectories with the main urban form attributes to allow the modeling experiment. The results show that the built environment features play an important role as a decision attribute, producing perceived utility/disutility on the decision-makers´ minds. They indicated that, in addition to the basic travel effort attributes such as trip distance or street slope, other factors such as the straightness of the trip, the road hierarchy, the presence of busy intersections, landmark buildings, noticeable public spaces and the density of buildings along the walking stretches indeed influence the route choice. The relatively small sample size and the spatial clustering of trips around the city´s central area doesn´t allow to the generalization of results. However, the study can be taken as a valid exploratory analysis, since it builds up a methodology that can be expanded and applied in other urban contexts. Furthermore, the results reveal some particular local features that indicate the existence of significant behavioral differences from the developed cities where previous similar studies were performed. These qualities make the proposed framework a promising decision support tool for sustainable urban mobility projects in Brazil.

abstract: Consumers search before making virtually any purchase. The notion that consumers engage in costly search is well-understood to have deep implications for market performance. However to date, no theoretical model allows for the observation that consumers often purchase more than a single product in an individual shopping occasion. Clothing, food, books, and music are but four important examples of goods that are purchased many items at a time. I develop a modeling approach that accounts for multi-purchase occasions in a structural way. My model shows that as preference for variety increases, so does the size of the consideration set. Search models that ignore preference for variety are, therefore, likely to under-predict the number of products searched. It is generally thought that lower search costs increase retail competition which pushes prices and assortments down. However, I show that there is an optimal number of products to offer depending on the intensity of consumer search costs. Consumers with high search costs prefer to shop at a store with a large assortment of goods and purchase multiple products, even if the prices that firm charges is higher than competing firms' prices. On the other hand, consumers with low search costs tend to purchase fewer goods and shop at the stores that have lower prices, as long as the store has a reasonable assortment offering. The implications for market performance are dramatic and pervasive. In particular, the misspecification of demand model in which search is important and/or multiple discreteness is observed will produce biased parameter estimates leading to erroneous managerial conclusions. / Dissertation/Thesis / Ph.D. Business Administration 2013

O estímulo aos modos ativos de viagem através de modificações na forma urbana - infraestrutura, edificações e atividades - é objeto do planejamento das cidades contemporâneas desde que os problemas do transporte motorizado se revelaram críticos e contrários à ideia de sustentabilidade urbana. Congestionamentos, poluição, custos monetários e sociais elevados estão associados ao modelo de urbanização e mobilidade da maioria das cidades, especialmente nos países em desenvolvimento, onde a explosão da frota motorizada é concomitante à aceleração dos processos de urbanização e espalhamento urbano. Mais recentemente, a revelação de relações de causalidade entre o excesso de utilização dos veículos particulares e problemas de saúde crônica das populações urbanas levou a um crescimento das pesquisas e iniciativas de estímulo às caminhadas como modo de transporte. Também o interesse pela qualidade da experiência da vida na cidade veio somar-se a este corpo de conhecimento, trazendo as ideias de vitalidade urbana e urbanidade para junto dos estudos de caminhabilidade. O interesse extrapolou a análise de demanda agregada que visa o incremento do modo a pé e passou a dar atenção aos caminhos pelos quais as pessoas se movimentam, conectando origens e destinos nos interior das cidades. Este trabalho procura avançar neste aspecto ao propor um método de avaliação dos atributos da forma urbana baseado no monitoramento de caminhantes com dispositivos de posicionamento global (GPS) e modelos de escolha discreta. Um estudo na cidade de Porto Alegre acompanhou indivíduos durante os anos de 2011 a 2014 e, através da representação de diversos atributos urbanos em ambiente SIG, associou as trajetórias realizadas com as características da forma da cidade, concluindo que elas influenciam a utilidade percebida das alternativas de caminho e, portanto, atuam sobre o processo decisório dos pedestres. Para além da simples distância ou declividade, outras características como o tamanho dos trechos, a hierarquia das vias, a presença de prédios marcantes e espaços abertos e a densidade de edificações ao longo dos eixos revelaram-se influentes neste processo. Poucas intersecções e cruzamentos, predomínio de vias amigáveis ao pedestre e edificações arranjadas de forma menos densa são alguns dos atributos que apresentaram maior relevância para a decisão de “por onde ir” no âmbito deste estudo. A amostra relativamente pequena e a concentração das viagens no entorno do Parque Farroupilha e do campus da UFRGS não permitem generalizar os resultados. Porém, o estudo pode ser considerado válido enquanto exploração, pois constrói uma metodologia que pode ser ampliada e aplicada em outros contextos. Além disso, os resultados revelam particularidades da realidade local que parecem indicar a existência de diferenças comportamentais significativas em relação às cidades do primeiro mundo, tornando-o promissor como instrumento de suporte a políticas e projetos de mobilidade urbana sustentável no Brasil. / Since motorized transport problems have proved to be critical and contrary to the concept of urban sustainability, the idea of increasing the active travel modes through changes in urban form is a key subject of today´s mobility agenda. Traffic congestion, air pollution and severe monetary and social costs are associated with the current patterns of urbanization and mobility, especially in developing countries, where an explosive motorized fleet growth occurs simultaneously to an acceleration of urbanization and sprawl processes. Most recently evidences of a causal relationship between massive use of private vehicles and chronic health disorders have led to an increase in research about walking as an effective and clean mode of transportation. Also, the interest about the quality of life experience in the city came to add up to this body of knowledge, bringing in ideas of livability to walkability studies. Beyond the aggregate demand studies that aim to increase the walking mode share, there is now a growing interest on more localized aspects of the walking phenomenon - the routes - trying to understand the ways in which people travel on foot when connecting origins and destinations. This work proposes a method based on assessing data from actually taken walking trips using GPS devices and on modeling pedestrian´s choice behavior using discrete choice models. A study in the city of Porto Alegre, south of Brazil, followed 82 individuals for three consecutive days and, through the representation of several layers of urban data in a GIS environment, associated their trajectories with the main urban form attributes to allow the modeling experiment. The results show that the built environment features play an important role as a decision attribute, producing perceived utility/disutility on the decision-makers´ minds. They indicated that, in addition to the basic travel effort attributes such as trip distance or street slope, other factors such as the straightness of the trip, the road hierarchy, the presence of busy intersections, landmark buildings, noticeable public spaces and the density of buildings along the walking stretches indeed influence the route choice. The relatively small sample size and the spatial clustering of trips around the city´s central area doesn´t allow to the generalization of results. However, the study can be taken as a valid exploratory analysis, since it builds up a methodology that can be expanded and applied in other urban contexts. Furthermore, the results reveal some particular local features that indicate the existence of significant behavioral differences from the developed cities where previous similar studies were performed. These qualities make the proposed framework a promising decision support tool for sustainable urban mobility projects in Brazil.

Esta tese é composta por três ensaios sobre Economia do Empreendedorismo. O primeiro deles trata sobre os determinantes do empreendedorismo no Brasil a partir de modelos de escolha ocupacional, usando os microdados da Pesquisa Nacional por Amostra por Domicílios (PNAD) do ano de 2012. A estratégia empírica adotada empregou os modelos de escolha discreta na estimação da escolha ocupacional. Os resultados demonstraram que existem efeitos significativos para as variáveis: anos de estudos iniciais, sexo, estado civil assim como pensionista e aposentado. Para completar a análise foram estimadas as equações de rendimento, as quais explicam a escolha pela ocupação empreendedora em função dos ganhos relativos ao trabalho assalariado. Já o segundo ensaio tem como objetivo apresentar uma evidência empírica para a relação existente entre empreendedorismo e corrupção nos estados brasileiros, utilizando uma abordagem teórica e empírica. Este artigo utiliza um indicador objetivo de corrupção governamental estadual baseado no Cadastro de Contas Irregulares do Tribunal de Contas da União (CADIRREG) como proxy para a corrupção regional e a abertura de novas empresas per capita como medida para a atividade empreendedora. Foram utilizados o método de dados de painel estático, dinâmico e o método GMMSYS, estes últimos empregados para corrigir possíveis problemas de endogeneidade. Os resultados encontrados mostraram-se coerentes com a hipótese teórica “grease in the wheels”, na qual a corrupção influencia positivamente a atividade empreendedora em países em desenvolvimento com elevada burocracia. Por fim, o terceiro ensaio avalia os impactos do empreendedorismo via inovação a partir do Global Trade Analysis Project – GTAP, um modelo de equilíbrio geral computável (EGC), destacando os impactos no crescimento econômicoe no bem-estar geral da economia. Os resultados mostraram-se coerentes com a literatura da Economia do Empreendedorismo, mostrando que aumento no empreendedorismo conduz a uma elevação no crescimento econômico e bem-estar. / This thesis consists of three essays on the Economics Entrepreneurship. The first deals with the determinants of entrepreneurship in Brazil from occupational choice models, using the data from the National Household Sample Survey (PNAD) of 2012. The empirical strategy adopted has employed discrete choice models in the estimation of occupational choice. The results showed that there are significant effects on the variables: years of initial studies, gender, marital status as well as pensioners and retired. To complete the analysis were estimated earnings equations, which explains the choice by the entrepreneurial occupation in terms of earnings for paid employment. The second test aims to present empirical evidence for the relationship between entrepreneurship and corruption in the Brazilian states, using a theoretical and empirical approach. This article uses an objective indicator of state government corruption based on the Register of Irregular accounts of the Court of Audit (CADIRREG) as a proxy for regional corruption and the opening of new companies per capita as a measure for regional entrepreneurial activity. They used the method of static panel data, dynamic and GMM-SYS method to correct the endogeneity problem. The results proved to be consistent with the theoretical hypothesis "grease in the wheels" in which corruption positively influence the entrepreneurial activity in developing countries with high bureaucracy. Finally, the third test evaluates the impacts of entrepreneurship via innovation from the Global Trade Analysis Project - GTAP, a model of computable general equilibrium (CGE), highlighting the impacts on economic growth and overall well-being economy. The results were consistent with the literatureof Entrepreneurship Economics, showing that increased entrepreneurship leads to a rise in economic growth and well-being.

The United States (US) witnessed remarkable growth in annual long distance travel over the past few decades. Over half of the long distance travel in the US is made for pleasure, including visiting friends and relatives (VFR) and leisure activities. This trend could continue with increased use of information and communication technologies for socialization, and enhanced mobility being achieved using fuel-efficient (electric/hybrid) and technology enhanced vehicles. Despite these developments, and recent interest to implement alternate mass transit options to serve this market, not much exists on the measurement, analysis and modeling of long distance pleasure travel in the U.S. Statewide and national models are used to estimate long distance travel, but these are predominantly trip-based models, making it difficult to understand long distance trips as collection of household-level travel behavior. This form of travel behavior has been studied a lot in tourism, but in a piecemeal manner, such as to (from) a specific destination. Further, most of these studies are confined to analyzing leisure market, with VFR market gaining recognition only recently. In essence, annual household long distance pleasure travel behavior needs to be studied in a comprehensive manner rather than as isolated trips. This is because, most of these household travel decisions are undertaken considering their annual time and monetary budget, and their perceived cost to travel to one (or more) destination for given pleasure purpose on one (or more) occasion using a given mode of travel. Thus, the main objective of this dissertation is to develop a comprehensive behavioral model framework to analyze the above-discussed annual household long distance pleasure travel choices. To start the above effort, it is first required to collect detailed annual household travel data, last collected over two decades ago (e.g.: ATS, 1995). No such recent effort has been pursued due to the significant labor and economic resource required to undertake it. There exist recent surveys (NHTS, 2001), but collected over a shorter (four week) period, and require significant processing even to arrive at aggregate annual travel estimates. Second, besides surveys, there is a need for additional data to estimate households’ annual pleasure travel budget, and their cost to travel and stay at each of their potential destination choices, which are not readily available. Thus, as the first goal, this dissertation analyzes long distance travel reported across historical surveys (NPTS; ATS; NHTS), to understand the differences in their definition, enumeration of purpose and collection methods. The intent here is twofold, first to conceive a method to estimate annual travel from surveys with shorter collection period. Further, the second intent is to gather travel patterns from these historical datasets such that it informs the second goal of this dissertation, i.e. development of a behavioral framework to analyze annual household pleasure travel. To this effect, this research also analyzes pleasure expenditures using Consumer Expenditure Survey (CEX, BLS) data. Interestingly, the analysis reveals CEX pleasure travel expenditure pattern to be similar to the travel pattern reported for the same market segments in travel survey (ATS). Importantly, the above analysis informs the development of behavioral models, pursued as two distinct tasks to achieve the second goal. As the first task, a novel econometric model and forecasting procedure is developed to analyze a household’s annual long distance leisure travel decisions. Specifically, a households’ time spent across one (or more) destination and travel mode to such destination for leisure is modeled subject to time and money budget constraints. In this methodological framework, the destination choice is modeled as a continuous variable (time at destination) using Multiple-Discrete Continuous Extreme Value model (MDCEV). While, travel mode choice to these destination(s) are modeled as a discrete choice, through a nested Multinomial Logit Model (MNL), with price variation introduced across the above choice of destination(s) and travel modes (air/ground). This required estimating annual monetary budgets, travel cost and per night lodging cost for each sample household, with each of them having 210 potential destinations and 2 travel mode choices respectively. The second task, involved the development of a broader national model system to analyze households’ annual pleasure travel decisions such as: choice (duration) at destination(s), travel purpose (VFR or leisure), mode (airplane or auto) choice and trip frequencies to these destination(s) using the same dataset. It was modeled in two stages, with the first stage estimating households’ annual pleasure time budget using a stochastic frontier model. This budget was then used as constraint to analyze households’ annual choice of destination and purpose using a nested MDCEV-MNL model in the second stage. A log sum variable from a nested joint multinomial logit model of trip frequency and mode choice for each purpose (VFR or leisure) is also introduced as input at this stage. This model was then validated using a prediction procedure, and further applied to test a policy scenario (increase in travel cost). The above national pleasure travel demand model could be further enhanced by including monetary constraints and price variation as in the first task. Overall, the model system proposed in this dissertation forms the foundation for a national comprehensive long distance travel model. This could be achieved through inclusion of other prominent travel purpose such as business and commuting to the national travel demand model presented in this research.

This study had two main objectives. One objective was to measure the aggregate impact of climate change on income from all agricultural production systems (crop, livestock and mixed) in Africa and to predict future impacts under various climate scenarios. In addition to measuring economic impacts, the study analysed determinants of farmers’ choices between alternative adaptation measures available to African farmers. The study is based on a cross-section survey of over 8000 farming households from 11 countries in east, west, north and southern Africa. To achieve the first objective, the cross-section (Ricardian) approach was used to measure the impact of climate change attributes (rainfall and temperature levels) on income from all agricultural production systems (crop, livestock and mixed) in Africa, controlling for other production factors. Based on empirical estimates from the Ricardian model, the study predicts future impacts under various climate scenarios. In addition to estimating impacts on mixed croplivestock farms, the study also measures and compares impacts on specialised crop and livestock farms. Responses of different production systems are analysed under irrigation and dryland conditions. The response of net revenue from crop and livestock agriculture across various farm types and systems in Africa, to changes in climate variables (i.e. mean rainfall and temperature) is analysed. The analysis controlled for effects of key socio-economic, technology, soil and hydrological factors influencing agricultural production. In addition to measuring impacts on aggregate revenue, the study examined variations in the response of three distinct production systems characterising African agriculture: specialised crop; specialised livestock and mixed crop and livestock systems. Differential impacts of climate change on the studied systems were measured under irrigation and dryland conditions. Results show that net farm revenues are in general negatively affected by warmer and dryer climates. The mixed crop and livestock system predominant in Africa is the most tolerant, whereas specialised crop production is the most vulnerable to warming and lower rainfall. These results have important policy implications, especially in terms of the suitability of the increasing tendency toward mono-cropping strategies for agricultural development in Africa and other parts of the developing world, in the light of expected climate changes. Mixed crop and livestock farming and irrigation offered better adaptation options for farmers against further warming and drying predicted under various future climate scenarios. For the second objective, the study employed a multinomial choice model to analyse determinants of farm-level climate adaptation measures in Africa. Results indicate that specialised crop cultivation (mono-cropping) is the most vulnerable agricultural practice in Africa in the face of climate change. Warming, especially in summer, poses the highest climate risk which tends to indicate switching away from mono-cropping towards the use of irrigation, multiple cropping and integration of livestock activities. Increased precipitation reduces the need for irrigation and will be beneficial to most African farming systems, especially in drier areas. Better access to markets, agricultural extension and credit services, technology and farm assets (such as labour, land and capital) are critical enabling factors to enhance the capacity of African farmers to adapt to climate change. Government policies and investment strategies that support the provision of and access to education, markets, credit, and information on climate and adaptation measures, including suitable technological and institutional mechanisms that facilitate climate adaptation, are therefore required for coping with climate change, particularly among poor resource farmers in the dry areas of Africa. / Thesis (PhD)--University of Pretoria, 2009. / Agricultural Economics, Extension and Rural Development / unrestricted

This thesis treats with the theory, interpretation and application of the Discrete Choice Models. The theoretical part contains the Fitting the Logistic Regression Model, Testing for the Significance of the Coefficients, Testing for the Significance of the Model. The Multiple Logistic Regression is mentioned too. The model was applied to interview data from the International research called Reflex.