Due to the inherently hierarchical nature of many natural phenomena, data collected rests in nested entities. As an example, students are nested in schools, school are nested in districts, districts are nested in counties, and counties are nested within states. Multilevel models provide a statistical framework for investigating and drawing conclusions regarding the influence of factors at differing hierarchical levels of analysis. The work in this paper serves as an introduction to multilevel models and their comparison to Ordinary Least Squares (OLS) regression. We overview three basic model structures: variable intercept model, variable slope model, and hierarchical linear model and illustrate each model with an example of student data. Then, we contrast the three multilevel models with the OLS model and present a method for producing confidence intervals for the regression coefficients. / text

This dissertation describes the development of a requirements analysis methodology that takes into account the concept of operations and the hierarchical decomposition of aerospace systems. At the core of the methodology, the Analytic Network Process (ANP) is used to ensure the traceability between the qualitative and quantitative information present in the hierarchical model. The proposed methodology is implemented to the requirements definition of a hurricane tracker Unmanned Aerial Vehicle. Three research objectives are identified in this work; (1) improve the requirements mapping process by matching the stakeholder expectations with the concept of operations, systems and available resources; (2) reduce the epistemic uncertainty surrounding the requirements and requirements mapping; and (3) improve the requirements down-selection process by taking into account the level of importance of the criteria and the available resources. Several challenges are associated with the identification and definition of requirements. The complexity of the system implies that a large number of requirements are needed to define the systems. These requirements are defined early in the conceptual design, where the level of knowledge is relatively low and the level of uncertainty is large. The proposed methodology intends to increase the level of knowledge and reduce the level of uncertainty by guiding the design team through a structured process. To address these challenges, a new methodology is created to flow-down the requirements from the stakeholder expectations to the systems alternatives. A taxonomy of requirements is created to classify the information gathered during the problem definition. Subsequently, the operational and systems functions and measures of effectiveness are integrated to a hierarchical model to allow the traceability of the information. Monte Carlo methods are used to evaluate the variations of the hierarchical model elements and consequently reduce the epistemic uncertainty. The proposed methodology is applied to the design of a hurricane tracker Unmanned Aerial Vehicles to demonstrate the origin and impact of requirements on the concept of operations and systems alternatives. This research demonstrates that the hierarchical modeling methodology provides a traceable flow-down of the requirements from the problem definition to the systems alternatives phases of conceptual design.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Esta tese tem o objetivo geral de investigar a associação entre estresse e acidentes no trabalho em funcionários técnico-administrativos efetivos de uma universidade pública no Rio de Janeiro por meio de modelos multiníveis. Para alcançar tal objetivo, a tese foi distribuída em dois artigos. O primeiro artigo investiga a associação entre estresse e acidentes no trabalho considerando componentes hierárquicos da estrutura dos dados por meio de modelos multiníveis com funcionários no primeiro nível agrupados em setores de trabalho no segundo nível. O segundo artigo investiga o comportamento dos coeficientes fixos e aleatórios dos modelos multiníveis com classificação cruzada entre setores de trabalho e grupos ocupacionais em relação aos modelos multiníveis que consideram apenas componentes hierárquicos dos setores de trabalho, ignorando o ajuste dos grupos ocupacionais. O estresse psicossocial no trabalho foi abordado a partir das relações entre alta demanda psicológica e baixo controle do processo laboral, Estas dimensões foram captadas por meio da versão resumida da escala Karasek, que também contém informações sobre o apoio social no trabalho. Dimensões isoladas do estresse no trabalho (demanda e controle), razão entre demanda psicológica e controle do trabalho (Razão D/C) e o apoio social no trabalho foram mensurados no nível individual e nos setores de trabalho. De modo geral, os resultados destacam a demanda psicológica mensurada no nível individual como um importante fator associado à ocorrência de acidentes de trabalho. O apoio social no trabalho, mensurado no nível individual e no setor de trabalho, apresentou associação inversa à prevalência de acidentes de trabalho, sendo, no setor, acentuada entre as mulheres. Os resultados também mostram que os parâmetros fixos dos modelos com e sem classificação cruzada foram semelhantes e que, de modo geral, os erros padrões (EP) foram um pouco maiores nos modelos com classificação cruzada, apesar deste comportamento do EP não ter sido observado quando relacionado aos coeficientes fixos das variáveis agregadas no setor de trabalho. A maior distinção entre as duas abordagens foi observada em relação aos coeficientes aleatórios relacionados aos setores de trabalho, que alteraram substancialmente após ajustar o efeito da ocupação por meio dos modelos com classificação cruzada. Este estudo reforça a importância de características psicossociais na ocorrência de acidentes de trabalho e contribui para o conhecimento dessas relações a partir de abordagens analíticas que refinam a captação da estrutura de dependência dos indivíduos em seu ambiente de trabalho. Sugere-se a realização de outros estudos com metodologia similar, que permitam aprofundar o conhecimento sobre estresse e acidentes no trabalho. / This thesis has the general aim of investigating the association between stress and accidents at work with public employees at a public university in Rio de Janeiro, by means of multilevel models. To reach this goal, this study has been distributed into two articles. The first one investigates the association between stress and accidents at work taking into consideration hierarchic components in the data structure by means of multilevel models with employees in the first level grouped in working areas in the second level. The second article investigates the behavior of random and fixed coefficients of the multilevel models with cross classification between working areas and occupational groups in relation to the multilevel models which only take into consideration hierarchic components of the working areas, ignoring the adjustment of occupational groups. The psychosocial stress at work was approached from the relation between high psychological demand and low labor process control. These dimensions were taken by means of the summarized version of the Karasek scale, which also contains information about the social support at work. Isolated dimensions of work stress (demand and control), the ratio between psychological demand and work control (ratio D/C) and the social support at work were measured at individual level and at working areas. Generally speaking, the results highlighted the psychological demand measured at individual level with a major aspect associated to accidents occurrence at work. The social support at work, measured at individual level and in the working area, presented inverted association to the prevalence of accidents at work, that association being more present among women. The results also show that the fixed parameters of the models with and without cross classification were similar and that, in general, the stander errors (SE) were a little bigger in the models with cross classification, although this behavior of the SE hasnt been observed when related to the fixed coefficient of the variable measured at working area. The major distinction between the two approaches was observed in relation to random coefficients related to the working areas, which were highly altered after adjusting the effect of the occupation by means of models with cross classification. This thesis reinforces the importance of psychosocial characteristics in the occurrence of accidents at work and contributes to the knowledge of these relations from analytical approaches which refine the gathering of the dependence structure of individuals in their working place. Its suggested that other studies with similar methodologies are made, that would allow us to go deep in the knowledge of stress and accidents at work.

Le point de départ de cette recherche concerne la question suivante : l’acquisition de la lecture, peut-il être plus ou moins efficace en fonction de la langue dans laquelle il s’effectue? Deux catégories pour classer les langues on été définies dans ce travail. Premièrement, la notion de famille linguistique est à la base d’une description des langues à partir d'une perspective historique et culturelle. Deuxièmement la notion de profondeur orthographique est mobilisée, celle-ci différencie les langues en fonction de la correspondance entre l'orthographe et la phonétique. Ces catégories ont été mises en rapport avec les bases de données PIRLS 2001 et 2006 (étude internationale sur la lecture menée par l'IEA), afin de relier la performance en lecture et la langue dans laquelle les élèves ont répondu au test. Toutefois, il est clair que la langue n'est pas un facteur isolé, car elle fait partie d'un ensemble complexe de déterminants; ainsi, des facteurs liés aux élèves et au milieu scolaire ont également été incorporés dans l'étude. En outre, il a été tenu compte de la multidimensionnalité du processus de lecture, en distinguant dans les analyses les différents domaines mesurés par l’enquête : lecture d'informative, littéraire, et compréhension des processus d'ordre complexe et simple. Pour répondre aux questions de cette recherche nous avons élaboré un modèle statistique hiérarchique capable de rendre compte de la relation entre la compréhension de la lecture, la langue et les facteurs qui y sont associés. En dernière analyse, les facteurs contextuels (individuels et scolaires) se sont révélés être plus importants que la langue elle-même. En outre, les déterminants du niveau en lecture dépendent des systèmes éducatifs observés dans cette enquête. / The starting point of this research is the question, may reading acquisition be more or less effective depending on the language in which it is perform? Two categories for classifying the languages have been developed. First the notion of linguistic family is employed to describe the languages from a cultural and historical perspective. Secondly, the notion of orthographic depth is used for differentiating the languages according to the correspondence between orthography and phonetic. These categories have been related to the databases PIRLS 2001 and 2006 (international assessments about reading developed by the IEA), the aim being to connect reading achievement to the language in which students answered the test. However, it is clear that the language is not an isolated factor, but part of a complex structure of determinants of reading. Therefore, factors related to students and schools have also been incorporated to this research. Moreover, the multidimensionality of the reading process has been taken into account by distinguishing in the analysis the different aspects that made the process according to PIRLS: informative reading, literary reading, process comprehension of high and low order. To answer to the questions proposed by this research a hierarchical statistical model (multilevel) was developed, it was able to account for the connection between reading achievement, language and other associated factors. As a result, contextual factors (home and school) were more significant than language. Moreover, determinacy may vary if taking into account educational systems.

CONTEXTO: O Coeficiente de Mortalidade Infantil (CMI), que expressa o risco de um nascido vivo morrer antes de completar um ano de vida, é considerado um dos mais eficientes sensores de desenvolvimento social, econômico e ético, e seu acompanhamento permite inferir sobre a qualidade de vida de uma população. No Rio Grande do Sul, esse coeficiente vem apresentando tendência decrescente, permanecendo abaixo da média nacional. Entretanto, ampliar a compreensão dos determinantes da mortalidade infantil pode contribuir na elaboração de políticas e programas de saúde específicos. São inúmeros os fatores de risco citados na literatura, e a maioria deles é evidenciada em estudos que desconsideram a hierarquia existente nos dados. Porém, crianças que vivem em determinadas regiões podem apresentar características similares, quando comparadas a outras que vivem em regiões diferentes. Assim, as técnicas clássicas de análise, que pressupõem independência entre as observações, podem produzir estimativas viesadas. OBJETIVOS: O objetivo deste estudo foi utilizar os dados de sistemas de informações para analisar a evolução e os determinantes da mortalidade infantil e seus componentes no Rio Grande do Sul, de 1994 a 2004, assim como identificar os fatores associados à mortalidade neonatal, em 2003, considerando características individuais e contextuais. MÉTODO: Para a análise da evolução, foi realizado um estudo ecológico longitudinal, considerando-se medidas repetidas e regressão linear multinível, com microrregiões no nível 2 e tempo no nível 1. Para identificar os determinantes associados ao óbito neonatal, foi utilizada uma coorte retrospectiva que vinculou os nascimentos registrados no período de 01/01/2003 a 03/12/2003 aos óbitos neonatais originados desses nascimentos. Esses fatores foram estimados e comparados por meio da análise dos modelos de regressão logística clássica e multinível. RESULTADOS: Verificou-se que a taxa de mortalidade infantil reduziu de 19,2 para 15,2 por mil nascidos vivos, e as principais causas de óbitos infantis, nos últimos cinco anos, foram as afecções perinatais (54,10%). Aproximadamente 47% da variação nas taxas de mortalidade ocorreu no nível das microrregiões, sendo que 10% de acréscimo na cobertura do Programa Saúde da Família esteve associado à redução de 1‰ na mortalidade infantil, e um acréscimo de 10% na taxa de pobreza esteve associado com uma redução de 2,1‰ nos óbitos infantis. Também, encontrou-se associação positiva com a proporção de baixo peso e a taxa de leitos hospitalares na população e, negativa, com a proporção de partos cesáreos e a taxa de hospitais. As variáveis associadas ao óbito neonatal, no modelo clássico, foram: baixo peso ao nascer, Apgar no 1º e 5º minuto inferiores a 8, presença de anomalia congênita, parto cesáreo, prematuridade e perda fetal anterior. No modelo multinível, essa variável não se manteve significativa, mas a inclusão da variável contextual indicou que 15% da variação da mortalidade neonatal pode ser explicada pela variabilidade nas taxas de pobreza em cada microrregião. CONCLUSÕES: Este estudo evidenciou a predominância dos fatores individuais na mortalidade infantil e neonatal, mas demonstrou que a análise multinível foi capaz de identificar efeitos contextuais, possibilitando ações públicas direcionadas aos grupos vulneráveis. / CONTEXT: The Infant Mortality Coefficient (IMC), that express the risk of a bornalive baby die before completing one year of life, is considered one of the most efficient sensors of social, economic and ethical development, and its following allows to infer on the population life quality. In Rio Grande do Sul this coefficient has presented a decreasing trend, remaining below national average. However, to extend the understanding determinants of infant mortality can contribute in the elaboration of policies and specific health programs. Several risk factors are mentioned in literature, and the majority of them are evidenced in studies that disrespect the existing hierarchy in data. However, children who live in certain regions can present similar characteristics, when compared to others who live in different regions. Thus, classical techniques of analysis that estimate independence between comments, can produce biased estimates. OBJECTIVES: The objective of this study was to use the systems of information data to analyze the evolution and determinants of infant mortality and their components in Rio Grande do Sul from 1994 to 2004, as well as to identify the factors associated to neonatal mortality, in 2003, considering individual and contextual characteristics. METHOD: For the evolution analysis a longitudinal ecologic study was carried out, considering repeated-measures and multilevel linear regression, with microregions in level 2 and time in level 1. To identify the determinants associated to neonatal death, a historic cohort was used to link births recorded from 01/01/2003 to 12/03/2003 with the originated neonatal deaths of these births. These factors were estimated and compared by classic and multilevel logistic regression models. RESULTS: It was verified that the infant mortality rate decreased from 19.2 to 15.2 per thousand live births, and the main causes of infant deaths in the last five years has been perinatal affections (54.10%). Approximately 47% of the variation in mortality rates occurred at a microregion level, being that 10% increase in Family Health Program coverage was associated to the reduction of 1‰ in infant mortality, and an increase of 10% in poverty rate was associated to an increase of 2.1‰ in infant deaths. Also, there was positive association with the proportion of low weight and hospital bed rates in the population and, negative, with the proportion of caesarean sections and hospital rates. Low birthweight, Apgar scores at 1 and at 5 minutes lower 8, presence of congenital abnormality, caesarean section, pre-term birth and previous fetal loss were associated to neonatal deaths in the classical model. In the multilevel model, previous fetal loss did not remain significant, but the inclusion of contextual variable indicated that 15% of neonatal mortality variation can be explained by the variability in rates of poverty in each microregion. CONCLUSIONS: This study evidenced the predominance of individual factors in infant and neonatal mortality, but it demonstrated that the multilevel analysis was capable of identifying contextual effects, making directed actions to the susceptible groups possible.

Conselho Nacional de Desenvolvimento Científico e Tecnológico / Esta tese tem o objetivo geral de investigar a associação entre estresse e acidentes no trabalho em funcionários técnico-administrativos efetivos de uma universidade pública no Rio de Janeiro por meio de modelos multiníveis. Para alcançar tal objetivo, a tese foi distribuída em dois artigos. O primeiro artigo investiga a associação entre estresse e acidentes no trabalho considerando componentes hierárquicos da estrutura dos dados por meio de modelos multiníveis com funcionários no primeiro nível agrupados em setores de trabalho no segundo nível. O segundo artigo investiga o comportamento dos coeficientes fixos e aleatórios dos modelos multiníveis com classificação cruzada entre setores de trabalho e grupos ocupacionais em relação aos modelos multiníveis que consideram apenas componentes hierárquicos dos setores de trabalho, ignorando o ajuste dos grupos ocupacionais. O estresse psicossocial no trabalho foi abordado a partir das relações entre alta demanda psicológica e baixo controle do processo laboral, Estas dimensões foram captadas por meio da versão resumida da escala Karasek, que também contém informações sobre o apoio social no trabalho. Dimensões isoladas do estresse no trabalho (demanda e controle), razão entre demanda psicológica e controle do trabalho (Razão D/C) e o apoio social no trabalho foram mensurados no nível individual e nos setores de trabalho. De modo geral, os resultados destacam a demanda psicológica mensurada no nível individual como um importante fator associado à ocorrência de acidentes de trabalho. O apoio social no trabalho, mensurado no nível individual e no setor de trabalho, apresentou associação inversa à prevalência de acidentes de trabalho, sendo, no setor, acentuada entre as mulheres. Os resultados também mostram que os parâmetros fixos dos modelos com e sem classificação cruzada foram semelhantes e que, de modo geral, os erros padrões (EP) foram um pouco maiores nos modelos com classificação cruzada, apesar deste comportamento do EP não ter sido observado quando relacionado aos coeficientes fixos das variáveis agregadas no setor de trabalho. A maior distinção entre as duas abordagens foi observada em relação aos coeficientes aleatórios relacionados aos setores de trabalho, que alteraram substancialmente após ajustar o efeito da ocupação por meio dos modelos com classificação cruzada. Este estudo reforça a importância de características psicossociais na ocorrência de acidentes de trabalho e contribui para o conhecimento dessas relações a partir de abordagens analíticas que refinam a captação da estrutura de dependência dos indivíduos em seu ambiente de trabalho. Sugere-se a realização de outros estudos com metodologia similar, que permitam aprofundar o conhecimento sobre estresse e acidentes no trabalho. / This thesis has the general aim of investigating the association between stress and accidents at work with public employees at a public university in Rio de Janeiro, by means of multilevel models. To reach this goal, this study has been distributed into two articles. The first one investigates the association between stress and accidents at work taking into consideration hierarchic components in the data structure by means of multilevel models with employees in the first level grouped in working areas in the second level. The second article investigates the behavior of random and fixed coefficients of the multilevel models with cross classification between working areas and occupational groups in relation to the multilevel models which only take into consideration hierarchic components of the working areas, ignoring the adjustment of occupational groups. The psychosocial stress at work was approached from the relation between high psychological demand and low labor process control. These dimensions were taken by means of the summarized version of the Karasek scale, which also contains information about the social support at work. Isolated dimensions of work stress (demand and control), the ratio between psychological demand and work control (ratio D/C) and the social support at work were measured at individual level and at working areas. Generally speaking, the results highlighted the psychological demand measured at individual level with a major aspect associated to accidents occurrence at work. The social support at work, measured at individual level and in the working area, presented inverted association to the prevalence of accidents at work, that association being more present among women. The results also show that the fixed parameters of the models with and without cross classification were similar and that, in general, the stander errors (SE) were a little bigger in the models with cross classification, although this behavior of the SE hasnt been observed when related to the fixed coefficient of the variable measured at working area. The major distinction between the two approaches was observed in relation to random coefficients related to the working areas, which were highly altered after adjusting the effect of the occupation by means of models with cross classification. This thesis reinforces the importance of psychosocial characteristics in the occurrence of accidents at work and contributes to the knowledge of these relations from analytical approaches which refine the gathering of the dependence structure of individuals in their working place. Its suggested that other studies with similar methodologies are made, that would allow us to go deep in the knowledge of stress and accidents at work.

CONTEXTO: O Coeficiente de Mortalidade Infantil (CMI), que expressa o risco de um nascido vivo morrer antes de completar um ano de vida, é considerado um dos mais eficientes sensores de desenvolvimento social, econômico e ético, e seu acompanhamento permite inferir sobre a qualidade de vida de uma população. No Rio Grande do Sul, esse coeficiente vem apresentando tendência decrescente, permanecendo abaixo da média nacional. Entretanto, ampliar a compreensão dos determinantes da mortalidade infantil pode contribuir na elaboração de políticas e programas de saúde específicos. São inúmeros os fatores de risco citados na literatura, e a maioria deles é evidenciada em estudos que desconsideram a hierarquia existente nos dados. Porém, crianças que vivem em determinadas regiões podem apresentar características similares, quando comparadas a outras que vivem em regiões diferentes. Assim, as técnicas clássicas de análise, que pressupõem independência entre as observações, podem produzir estimativas viesadas. OBJETIVOS: O objetivo deste estudo foi utilizar os dados de sistemas de informações para analisar a evolução e os determinantes da mortalidade infantil e seus componentes no Rio Grande do Sul, de 1994 a 2004, assim como identificar os fatores associados à mortalidade neonatal, em 2003, considerando características individuais e contextuais. MÉTODO: Para a análise da evolução, foi realizado um estudo ecológico longitudinal, considerando-se medidas repetidas e regressão linear multinível, com microrregiões no nível 2 e tempo no nível 1. Para identificar os determinantes associados ao óbito neonatal, foi utilizada uma coorte retrospectiva que vinculou os nascimentos registrados no período de 01/01/2003 a 03/12/2003 aos óbitos neonatais originados desses nascimentos. Esses fatores foram estimados e comparados por meio da análise dos modelos de regressão logística clássica e multinível. RESULTADOS: Verificou-se que a taxa de mortalidade infantil reduziu de 19,2 para 15,2 por mil nascidos vivos, e as principais causas de óbitos infantis, nos últimos cinco anos, foram as afecções perinatais (54,10%). Aproximadamente 47% da variação nas taxas de mortalidade ocorreu no nível das microrregiões, sendo que 10% de acréscimo na cobertura do Programa Saúde da Família esteve associado à redução de 1‰ na mortalidade infantil, e um acréscimo de 10% na taxa de pobreza esteve associado com uma redução de 2,1‰ nos óbitos infantis. Também, encontrou-se associação positiva com a proporção de baixo peso e a taxa de leitos hospitalares na população e, negativa, com a proporção de partos cesáreos e a taxa de hospitais. As variáveis associadas ao óbito neonatal, no modelo clássico, foram: baixo peso ao nascer, Apgar no 1º e 5º minuto inferiores a 8, presença de anomalia congênita, parto cesáreo, prematuridade e perda fetal anterior. No modelo multinível, essa variável não se manteve significativa, mas a inclusão da variável contextual indicou que 15% da variação da mortalidade neonatal pode ser explicada pela variabilidade nas taxas de pobreza em cada microrregião. CONCLUSÕES: Este estudo evidenciou a predominância dos fatores individuais na mortalidade infantil e neonatal, mas demonstrou que a análise multinível foi capaz de identificar efeitos contextuais, possibilitando ações públicas direcionadas aos grupos vulneráveis. / CONTEXT: The Infant Mortality Coefficient (IMC), that express the risk of a bornalive baby die before completing one year of life, is considered one of the most efficient sensors of social, economic and ethical development, and its following allows to infer on the population life quality. In Rio Grande do Sul this coefficient has presented a decreasing trend, remaining below national average. However, to extend the understanding determinants of infant mortality can contribute in the elaboration of policies and specific health programs. Several risk factors are mentioned in literature, and the majority of them are evidenced in studies that disrespect the existing hierarchy in data. However, children who live in certain regions can present similar characteristics, when compared to others who live in different regions. Thus, classical techniques of analysis that estimate independence between comments, can produce biased estimates. OBJECTIVES: The objective of this study was to use the systems of information data to analyze the evolution and determinants of infant mortality and their components in Rio Grande do Sul from 1994 to 2004, as well as to identify the factors associated to neonatal mortality, in 2003, considering individual and contextual characteristics. METHOD: For the evolution analysis a longitudinal ecologic study was carried out, considering repeated-measures and multilevel linear regression, with microregions in level 2 and time in level 1. To identify the determinants associated to neonatal death, a historic cohort was used to link births recorded from 01/01/2003 to 12/03/2003 with the originated neonatal deaths of these births. These factors were estimated and compared by classic and multilevel logistic regression models. RESULTS: It was verified that the infant mortality rate decreased from 19.2 to 15.2 per thousand live births, and the main causes of infant deaths in the last five years has been perinatal affections (54.10%). Approximately 47% of the variation in mortality rates occurred at a microregion level, being that 10% increase in Family Health Program coverage was associated to the reduction of 1‰ in infant mortality, and an increase of 10% in poverty rate was associated to an increase of 2.1‰ in infant deaths. Also, there was positive association with the proportion of low weight and hospital bed rates in the population and, negative, with the proportion of caesarean sections and hospital rates. Low birthweight, Apgar scores at 1 and at 5 minutes lower 8, presence of congenital abnormality, caesarean section, pre-term birth and previous fetal loss were associated to neonatal deaths in the classical model. In the multilevel model, previous fetal loss did not remain significant, but the inclusion of contextual variable indicated that 15% of neonatal mortality variation can be explained by the variability in rates of poverty in each microregion. CONCLUSIONS: This study evidenced the predominance of individual factors in infant and neonatal mortality, but it demonstrated that the multilevel analysis was capable of identifying contextual effects, making directed actions to the susceptible groups possible.

CONTEXTO: O Coeficiente de Mortalidade Infantil (CMI), que expressa o risco de um nascido vivo morrer antes de completar um ano de vida, é considerado um dos mais eficientes sensores de desenvolvimento social, econômico e ético, e seu acompanhamento permite inferir sobre a qualidade de vida de uma população. No Rio Grande do Sul, esse coeficiente vem apresentando tendência decrescente, permanecendo abaixo da média nacional. Entretanto, ampliar a compreensão dos determinantes da mortalidade infantil pode contribuir na elaboração de políticas e programas de saúde específicos. São inúmeros os fatores de risco citados na literatura, e a maioria deles é evidenciada em estudos que desconsideram a hierarquia existente nos dados. Porém, crianças que vivem em determinadas regiões podem apresentar características similares, quando comparadas a outras que vivem em regiões diferentes. Assim, as técnicas clássicas de análise, que pressupõem independência entre as observações, podem produzir estimativas viesadas. OBJETIVOS: O objetivo deste estudo foi utilizar os dados de sistemas de informações para analisar a evolução e os determinantes da mortalidade infantil e seus componentes no Rio Grande do Sul, de 1994 a 2004, assim como identificar os fatores associados à mortalidade neonatal, em 2003, considerando características individuais e contextuais. MÉTODO: Para a análise da evolução, foi realizado um estudo ecológico longitudinal, considerando-se medidas repetidas e regressão linear multinível, com microrregiões no nível 2 e tempo no nível 1. Para identificar os determinantes associados ao óbito neonatal, foi utilizada uma coorte retrospectiva que vinculou os nascimentos registrados no período de 01/01/2003 a 03/12/2003 aos óbitos neonatais originados desses nascimentos. Esses fatores foram estimados e comparados por meio da análise dos modelos de regressão logística clássica e multinível. RESULTADOS: Verificou-se que a taxa de mortalidade infantil reduziu de 19,2 para 15,2 por mil nascidos vivos, e as principais causas de óbitos infantis, nos últimos cinco anos, foram as afecções perinatais (54,10%). Aproximadamente 47% da variação nas taxas de mortalidade ocorreu no nível das microrregiões, sendo que 10% de acréscimo na cobertura do Programa Saúde da Família esteve associado à redução de 1‰ na mortalidade infantil, e um acréscimo de 10% na taxa de pobreza esteve associado com uma redução de 2,1‰ nos óbitos infantis. Também, encontrou-se associação positiva com a proporção de baixo peso e a taxa de leitos hospitalares na população e, negativa, com a proporção de partos cesáreos e a taxa de hospitais. As variáveis associadas ao óbito neonatal, no modelo clássico, foram: baixo peso ao nascer, Apgar no 1º e 5º minuto inferiores a 8, presença de anomalia congênita, parto cesáreo, prematuridade e perda fetal anterior. No modelo multinível, essa variável não se manteve significativa, mas a inclusão da variável contextual indicou que 15% da variação da mortalidade neonatal pode ser explicada pela variabilidade nas taxas de pobreza em cada microrregião. CONCLUSÕES: Este estudo evidenciou a predominância dos fatores individuais na mortalidade infantil e neonatal, mas demonstrou que a análise multinível foi capaz de identificar efeitos contextuais, possibilitando ações públicas direcionadas aos grupos vulneráveis. / CONTEXT: The Infant Mortality Coefficient (IMC), that express the risk of a bornalive baby die before completing one year of life, is considered one of the most efficient sensors of social, economic and ethical development, and its following allows to infer on the population life quality. In Rio Grande do Sul this coefficient has presented a decreasing trend, remaining below national average. However, to extend the understanding determinants of infant mortality can contribute in the elaboration of policies and specific health programs. Several risk factors are mentioned in literature, and the majority of them are evidenced in studies that disrespect the existing hierarchy in data. However, children who live in certain regions can present similar characteristics, when compared to others who live in different regions. Thus, classical techniques of analysis that estimate independence between comments, can produce biased estimates. OBJECTIVES: The objective of this study was to use the systems of information data to analyze the evolution and determinants of infant mortality and their components in Rio Grande do Sul from 1994 to 2004, as well as to identify the factors associated to neonatal mortality, in 2003, considering individual and contextual characteristics. METHOD: For the evolution analysis a longitudinal ecologic study was carried out, considering repeated-measures and multilevel linear regression, with microregions in level 2 and time in level 1. To identify the determinants associated to neonatal death, a historic cohort was used to link births recorded from 01/01/2003 to 12/03/2003 with the originated neonatal deaths of these births. These factors were estimated and compared by classic and multilevel logistic regression models. RESULTS: It was verified that the infant mortality rate decreased from 19.2 to 15.2 per thousand live births, and the main causes of infant deaths in the last five years has been perinatal affections (54.10%). Approximately 47% of the variation in mortality rates occurred at a microregion level, being that 10% increase in Family Health Program coverage was associated to the reduction of 1‰ in infant mortality, and an increase of 10% in poverty rate was associated to an increase of 2.1‰ in infant deaths. Also, there was positive association with the proportion of low weight and hospital bed rates in the population and, negative, with the proportion of caesarean sections and hospital rates. Low birthweight, Apgar scores at 1 and at 5 minutes lower 8, presence of congenital abnormality, caesarean section, pre-term birth and previous fetal loss were associated to neonatal deaths in the classical model. In the multilevel model, previous fetal loss did not remain significant, but the inclusion of contextual variable indicated that 15% of neonatal mortality variation can be explained by the variability in rates of poverty in each microregion. CONCLUSIONS: This study evidenced the predominance of individual factors in infant and neonatal mortality, but it demonstrated that the multilevel analysis was capable of identifying contextual effects, making directed actions to the susceptible groups possible.

Depuis des décennies, toutes les analyses convergent vers l’idée d’une relative inefficacité des systèmes éducatifs d’Afrique subsaharienne. Décrochage, redoublements, effectifs pléthoriques, faible qualité des acquis d’élèves, insuffisance et obsolescence des structures d’accueil, du matériel didactique et des enseignants, dont parfois les niveaux et qualité de formation restent quelque peu incertains, inadaptation des programmes d’enseignement. Bref, tels sont quelques uns des maux qui minent lesdits systèmes et confirment les constats établis par de nombreux rapports. Face à ce constat de faiblesse, les autorités éducatives, soutenues par l’aide internationale se sont mobilisées dans plusieurs pays en vue d’améliorer leurs systèmes respectifs aux plans qualitatif, quantitatif mais aussi d’équité car, il ne faut pas l’oublier, dans ces systèmes, le dimorphisme structurel et contextuel les rend fortement inégalitaires. Devant cette crise, l’une des solutions entrevues, avec effets à court et moyen terme, a consisté à revoir fondamentalement les programmes d’enseignement. Dans ce contexte, l’approche par les compétences qui constitue l’une des grandes évolutions de la recherche éducative de ces trois dernières décennies, a été retenue comme plus apte à répondre aux besoins éducatifs fondamentaux des populations scolarisées. Pour en cerner les contours et en apprécier le bienfondé, une analyse objective des résultats desdites réformes, dont certaines ont débuté depuis 1998 était nécessaire. Ainsi, cette recherche a pour objectif d’évaluer aussi bien la pertinence que le niveau d’efficacité des réformes curriculaires mises en œuvre dans trois pays d’Afrique francophone à savoir : le Bénin, le Gabon et Madagascar. Prenant appui sur les données issues du programme d’analyse des systèmes éducatifs d’Afrique francophone (PASEC) ainsi qu’une enquête ad hoc menée au Gabon, l’étude tente de cerner les déterminants de l’efficacité éducative à partir de l’analyse comparative des performances et d’une étude séquentielle des pratiques d’enseignement. Si les résultats ressortent des transformations réelles du point de vue des pratiques pédagogiques, les indicateurs de performances scolaires restent quant à eux assez décevants. Pour autant, avec les mesures d’accompagnement d’envergure qu’ont initiées les autorités éducatives de certains pays, on peut s’attendre à de bien meilleurs résultats dans le temps. / For decades, all analyzes converge on the idea of the relative inefficiency of education systems in sub-Saharan Africa. Dropout, repetition, overstaffing, low quality of learning student failure and obsolescence of facilities, teaching materials and teachers, including sometimes the levels and quality of education remain somewhat uncertain, inadequate educational programs. In short, these are some of the ills that plague these systems and confirm the findings made by many reports. Given this weakness finding, educational authorities, supported by international aid mobilized in many countries to improve their systems to qualitatively, but also quantitatively equity because we must not forget in these systems, the structural and contextual dimorphism makes them highly unequal. Faced with this crisis, one of the interviews solutions with short and medium-term effects has been to fundamentally rethink the curriculum. In this context, the competencies approach constitutes one of the major developments in educational research of the past three decades, was selected as most suitable to meet the basic educational needs of school populations. To define its contours and appreciate the merits, an objective analysis of the results of these reforms, some of which began in 1998 was necessary. Thus, this research aims to assess both the relevance that the level of effectiveness of curricular reforms implemented in three Francophone African countries namely: Benin, Gabon and Madagascar. Drawing on data from the educational systems analysis program in Francophone Africa (PASEC) and an ad hoc survey in Gabon, the study attempts to identify the determinants of educational effectiveness from the comparative performance analysis and a sequential study of teaching practices. If the results come out real transformations from the perspective of teaching practices, school performance indicators are in turn quite disappointing. However, with major support measures what initiated the educational authorities in some countries, we can expect much better results in time.

The objective of this study was to examine the association between risky sexual behavior and contextual factors related to economic resources, woman’s empowerment, and health facility characteristics among young women in Zomba district, Malawi. Secondary analyses of the Schooling, Income, and Health Risk (SIHR) study were undertaken. Four outcomes related to risky sexual behavior were examined: if participants had ever had sex, consistent condom use, and two scores measuring risk related to partner history and age during sexual activity. Regression models with cluster-robust standard errors and multilevel regression models were used to estimate associations; analyses were stratified by school enrolment status at baseline of the SIHR study and utilized weights to account for SIHR sampling design. For participants in school at baseline, the percent of girls enrolled in school at the community level was associated with ever having sex and consistent condom use. Belief in the right to refuse sex was protective against ever having sex, lower household education was associated with higher odds of ever having sex, and near rural and far rural residence was associated with decreased odds of condom. For participants not in school at baseline, lower individual education was associated with riskier scores related to age and partner history and lower household education was associated with lower age during sexual activity. Private or non-governmental health facilities were associated with decreased odds of condom use and higher age during sexual activity. In both strata, increasing age and near rural residence (within 16 kilometers of urban center) increased odds of ever having sex; lower educational achievement was associated with lower age during sexual activity. A history of pregnancy was associated with lower odds of condom use and riskier partner history. Risky sexual behavior is multifaceted and complex. While various factors related to women’s empowerment played a role, the most consistent variables associated with risky sexual behavior were those related to education. Interventions and programs seeking to reduce risky sexual behavior among young women, thereby reducing their risk of HIV infection, should continue to focus on improving access to education at multiple levels.