Estimation of Parameters in Random Effect Models with Incidence Matrix Uncertainty

Random effect models have been widely applied in many fields of research. However, models with uncertain design matrices for random effects have been little investigated before. In some applications with such problems, an expectation method has been used for simplicity. This method does not include the extra information of uncertainty in the design matrix is not included. The closed solution for this problem is generally difficult to attain. We therefore propose an two-step algorithm for estimating the parameters, especially the variance components in the model. The implementation is based on Monte Carlo approximation and a Newton-Raphson-based EM algorithm. As an example, a simulated genetics dataset was analyzed. The results showed that the proportion of the total variance explained by the random effects was accurately estimated, which was highly underestimated by the expectation method. By introducing heuristic search and optimization methods, the algorithm can possibly be developed to infer the 'model-based' best design matrix and the corresponding best estimates.

Association between levels of pentraxin 3 and incidence of chronic kidney disease in the elderly

OBJECTIVE: Higher levels of the novel inflammatory marker pentraxin 3 (PTX3) predict cardiovascular mortality in patients with chronic kidney disease (CKD). Yet, whether PTX3 predicts worsening of kidney function has been less well studied. We therefore investigated the associations between PTX3 levels, kidney disease measures and CKD incidence. METHODS: Cross-sectional associations between serum PTX3 levels, urinary albumin/creatinine ratio (ACR) and cystatin C-estimated glomerular filtration rate (GFR) were assessed in two independent community-based cohorts of elderly subjects: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, n = 768, 51% women, mean age 75 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 651, mean age 77 years). The longitudinal association between PTX3 level at baseline and incident CKD (GFR <60 mL( ) min(-1)  1.73 m(-) ²) was also analysed (number of events/number at risk: PIVUS 229/746, ULSAM 206/315). RESULTS: PTX3 levels were inversely associated with GFR [PIVUS: B-coefficient per 1 SD increase -0.16, 95% confidence interval (CI) -0.23 to -0.10, P < 0.001; ULSAM: B-coefficient per 1 SD increase -0.09, 95% CI -0.16 to -0.01, P < 0.05], but not ACR, after adjusting for age, gender, C-reactive protein and prevalent cardiovascular disease in cross-sectional analyses. In longitudinal analyses, PTX3 levels predicted incident CKD after 5 years in both cohorts [PIVUS: multivariable odds ratio (OR) 1.21, 95% CI 1.01-1.45, P < 0.05; ULSAM: multivariable OR 1.37, 95% CI 1.07-1.77, P < 0.05]. CONCLUSIONS: Higher PTX3 levels are associated with lower GFR and independently predict incident CKD in elderly men and women. Our data confirm and extend previous evidence suggesting that inflammatory processes are activated in the early stages of CKD and drive impairment of kidney function. Circulating PTX3 appears to be a promising biomarker of kidney disease.

February 2009: Tax Time

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Education, preferences for leisure, and the optimal income tax schedule

Recent advances in dynamic Mirrlees economies have incorporated the treatment of human capital investments as an important dimension of government policy. This paper adds to this literature by considering a two period economy where agents are di erentiated by their preferences for leisure and their productivity, both private information. The fact that productivity is only learnt later in an agent's life introduces uncertainty to agent's savings and human capital choices and makes optimal the use of multi-period tie-ins in the mechanism that characterizes the government policy. We show that optimal policies are often interim ine cient and that the introduction of these ine ciencies may take the form of marginal tax rates on labor income of varying sign and educational policies that include the discouragement of human capital acquisition. With regards to implementation, state-dependent linear taxes implement optimal savings, while human capital policies may require labor income taxes that depend directly on agents' schooling.

Yet another reason to tax goods

The optimal taxation of goods, labor and capital income is considered in a two period model where: i) private information changes through time; ii) savings are not observed, and; iii) savings a§ect preferences conditional on the realization of types. The simultaneous appearance of these three elements cause optimal commodity taxes to depend on o§-equilibrium savings. As a consequence, separability no longer su¢ ces for the uniform taxation prescription of Atkinson and Stiglitz (AS) to obtain. If preferences are homothetic AS is partially restored: taxes are uniform within periods, however, future consumption is taxed at a higher rate than current consumption.

Ideological changes and tax structure: Latin American countries during the nineties

Sabatini (2002) and Roberts and Wibbles (1999) Pointed Out That Voters in Latin American Countries are no Longer Choosing According to Their Ideological Preferences. Ashworth and Heyndels (2002) Showed That the Tax Choice In Oecd Countries Does not Follow the Ideological Pattern of Party Preferences. the Most Robust Result of This Work Shows That the Tax Choice in Latin American Countries Still Depends on This Ideological Preference. We Also Verified That Changes in the Tax Structure Depend on Changes Both in the Tax Burden and the Openness of the Economy

The effects of tax incentives for small firms on employment levels

This paper will examine the effects of tax incentives for small businesses on employment level evaluating a program with this purpose implemented in Brazil in the 1990s. We first develop a theoretical framework which guides both the de nition of the parameters of interest and their identi cation. Selection problems both into the treatment group and into the data sample are tackled by combining fixed effects methods and regression discontinuity design on alternative sub-samples of a longitudinal database of manufacturing firms. The results show that on the one hand the size composition of the treated fi rms may be changed due to the survival of some smaller firms that would have exited had it not been eligible to the program. On the other hand, the treated firms who do not depend on the program to survive do employ more workers.

Essays in macroeconomics and public finance

Esta tese dedica-se ao estudo dos sistemas tributários. Eu investigo como um sistema tributário afeta as escolhas dos indivíduos e consequentemente os recursos do país. Eu mostro como um sistema tributário induz as escolhas das pessoas, determinado assim as alocações de trabalho, produto e consumo da economia. No primeiro e segundo capítulo eu examino a taxação sobre os indivíduos, enquanto que no terceiro e quarto capítulos analiso a incidîncia tributária sobre os diferentes agentes da sociedade. No capítulo um, eu examino o sistema tributário ótimo, seguindo Mirrlees (1971) e Saez (2001). Eu mostro como seria este sistema tributário no Brasil, país com profunda desigualdade de renda entre os indivíduos. Ademais, eu investigo o sistema tributário afim, considerado uma alternativa entre os sistemas atual e o ótimo. No segundo capítulo eu analiso o sistema tributário conhecido como sacríficio igual. Mostro como o sistema tribuária derivado por Young (1987), redesenhado por Berliant and Gouveia (1993), se comporta no teste de eficiência derivado por Werning (2007). No terceiro e quarto capítulo eu examino como propostas de reforma tribuária afetariam a economia brasileira. No capítulo três investigo como uma reforma tributária atingiria as diferentes classes socias. No capítulo quatro, eu estudo as melhores direções para uma reforma tributária no Brasil, mostrando qual arranjo de impostos é menos ineficiente para o país. Por fim, investigo os efeitos de duas propostas de reforma tributária sobre a economia brasileira. Explicito quais os ganhos de produto e bem estar de cada proposta. Dedico especial atenção aos ganhos/perdas de curto prazo, pois estes podem inviabilizar uma reforma tributária, mesmo esta gerando ganhos de longo prazo.

Sacrifice and efficiency of the income tax schedule

We investigate the efficiency of equal sacrifice tax schedules in an economy which primitives are exactly those in Mirrlees (1971): a continuum of individuals with identical preferences defined over consumption and leisure who differ with respect to their labor market productivity. Using a separable specification for preferences we derive the minimum equal sacrifice allocation and recover the tax schedule that implements it. The separable specification allows us to use the methodology developed by Werning (2007b) to check whether the schedule is efficient, that is, whether there is no alternative tax schedule that raises more revenue while delivering less utility to no one. We find that inefficiency does not arise for most parametrizations we use to approximate the US economy. For the few cases for which inefficiency does arise, it does so only for very high levels of income and marginal tax rates.

Tax filing choices for the household under separable spheres bargaining

If household choices can be rationalized by the maximization of a well defined utility function, allowing spouses to file individually or jointly is equivalent to offering the envelope of the two tax schedules. If, instead, household ’preferences’ are constantly being redefined through bargaining, the option to file separately may affect outcomes even if it is never chosen. We use Lundberg and Pollak’s (1993) separate spheres bargaining model to assess the impact of filing options on the outcomes of primary and secondary earners. Threat points of the household’s bargain are given for each spouse by the utility that he or she attains as a follower of a counter-factual off-equilibrium Stackelberg game played by the couple. For a benchmark tax system which treats a couple’s average taxable income as if it were that of a single individual, we prove that if choices are not at kinks, allowing couples to choose whether to file jointly or individually usually benefits the secondary earner. In our numeric exercises this is also the case when choices are at kinks as well. These findings are, however, quite sensitive to the details of the tax system, as made evident by the examination of an alternative tax system.

Funding social sector activity in Brazil: a case study analysis of agency risk incidence and mitigation

Empresas e organizações sociais têm um papel cada vez mais importante no mercado brasileiro. Essas organizações - sejam elas com ou sem fins lucrativos –têm como objetivocausar um profundo e positivo impacto social.Ambas enfrentamtambém o mesmo desafio: financiar as suas operações. Recentemente, dois modelos inovadores de financiamento, o fundo de venture capitalVox Capital e o fundo de empréstimo social SITAWI, entraram no mercado brasileiro para solucionar esse desafio. Este estudo analisa ambos os fundos,associando o problema do financiamento de empresas e organizações sociais às teorias tradicionais de negócio. Mais especificamente, por meio de um estudo de caso,é avaliado se o risco de agência (agency risk) explica as práticas e o designcontratual utilizados pelos fundos. A pesquisa é baseada num estudo de Alemany e Scarlata (2010) sobre a estruturação dos negócios de fundos filantrópicos de capital empreendedor (PhVC, na sigla em inglês) na América do Norte e na Europa. Uma definição chave desse estudo é que organizações sem fins lucrativos, ao contrário daquelas com fins lucrativos, estão sujeitas a uma restrição de distribuição de lucros. Embora Alemany e Scarlata (2010) tivessem descobertoque parceria (stewardship), mais do que o problema de agência (agency problem), explica a estrutura dos negócios dos fundos PhVC, as implicações do presente estudo de caso para o Brasil são diferentes. Os resultados sugerem que o problema de agência,mais do que a parceria,descreve adequadamente os contratos analisados de financiamento. Detectou-seque cláusulas contratuais não foram apenas usadas para mitigar o risco de agênciaresultanteda ausência de uma restrição de distribuição de lucros, mas também para reger as estruturas cooperativas com organizações sem fins lucrativos. No caso de SITAWI, a restrição dos destinatários de fundos de distribuir lucros provou-se uma ferramenta efetiva para alinhar os interesses entre os financiadores e os destinatários dos fundos. Apesar daimplicação da presença de parceria, os contratos do fundo social contiveram cláusulas geralmente usadas para reduzir o risco de agência. No caso de Vox Capital, os destinatários dos fundos eram empresas com fins lucrativos, portanto não sujeitas à restrição de distribuição de lucros. O modelo de negócio de Vox Capital é organizado para impedir qualquer incidência potencial do problema de agência. Ambos os fundos, independentemente da estrutura jurídica dos beneficiários destes fundos, evidenciaram o intuito de garantir a aplicação de práticas de negócio utilizadas pelas empresas tradicionais do setor corporativo em vez daquelas utilizadas no setor social.

Políticas públicas em cidadania fiscal : análise do comportamento do cidadão usuário do Programa Todos com a Nota, do Governo do Estado de Pernambuco

O objetivo desta pesquisa foi verificar se a Campanha Todos com a Nota – Módulo Esportivo, instituída pelo Governo do Estado de Pernambuco, conscientiza ou não o cidadão acerca da importância social de sempre pedir a nota fiscal nas suas compras sujeitas à incidência do Imposto sobre a Circulação de Mercadorias e Serviços (ICMS), bem como inferir qual a proporção populacional conscientizada. O referencial teórico abraçou conhecimentos de diversos campos afetos à seara da necessidade de conscientização fiscal, tais como obediência tributária, evasão fiscal, Administração Tributária, comportamento do consumidor e do contribuinte, Educação Fiscal e cidadania fiscal. Para atingir o objetivo, foi realizada pesquisa de comportamento do consumidor nos postos de atendimento ao usuário da Campanha. O método utilizado foi uma pesquisa do tipo survey estruturada. Os resultados sugerem que a Campanha Todos com a Nota conscientiza, e a proporção de cidadãos conscientizados sobre a função social do tributo fica entre 5,34% e 10,66% da população de usuários do Módulo Esportivo, que se utiliza de cartões magnéticos para troca de notas/cupons fiscais por ingressos para assistir aos jogos dos campeonatos brasileiro e pernambucano de futebol profissional. Embora esta proporção pareça pequena, merecendo maior atenção da Administração Pública, se compararmos com a proporção de cidadãos que já ingressaram na Campanha conscientizados, a melhoria foi em torno de, no mínimo, 7,21 vezes, com 95% de confiança.

On the efficiency of equal sacrifice income tax schedules

In an economy which primitives are exactly those in Mirrlees (1971), we investigate the efficiency of labor income tax schedules derived under the equal sacrifice principle. Starting from a given government revenue level, we use Werning’s (2007b) approach to assess whether there is an alternative tax schedule to the one derived under the equal sacrifice principle that raises more revenue while delivering less utility to no one. For our preferred parametrizations of the problem we find that inefficiency only arises at very high levels of income. We also show how the multipliers of the Pareto problem may be extracted from the data and used to find the implicit marginal social weights associated with each level of income.