Cluster robust models are a kind of statistical models that attempt to estimate parameters considering potential heterogeneity in treatment effects. Absent heterogeneity in treatment effects, the partial and average treatment effect are the same. When heterogeneity in treatment effects occurs, the average treatment effect is a function of the various partial treatment effects and the composition of the population of interest. The first chapter explores the performance of common estimators as a function of the presence of heterogeneity in treatment effects and other characteristics that may influence their performance for estimating average treatment effects. The second chapter examines various approaches to evaluating and improving cluster structures as a way to obtain cluster-robust models. Both chapters are intended to be useful to practitioners as a how-to guide to examine and think about their applications and relevant factors. Empirical examples are provided to illustrate theoretical results, showcase potential tools, and communicate a suggested thought process. The third chapter relates to an open-source statistical software package for the Julia language. The content includes a description for the software functionality and technical elements. In addition, it features a critique and suggestions for statistical software development and the Julia ecosystem. These comments come from my experience throughout the development process of the package and related activities as an open-source and professional software developer. One goal of the paper is to make econometrics more accessible not only through accessibility to functionality, but understanding of the code, mathematics, and transparency in implementations.

O prejuízo causado por chuvas de granizo é um dos principais problemas enfrentados pelos produtores de maçã no Brasil e em outros países. O trabalho apresenta, a partir de uma revisão abrangente da literatura e pesquisas de campo realizadas em região produtora do Estado de Santa Catarina, uma caracterização do problema e das alternativas existentes para a definição de estratégias ótimas para o gerenciamento do risco existente. As alternativas consideradas incluíram: seguro comercial, seguro mútuo, diversificação espacial, telas anti- granizo, foguetes anti- granizo e geradores de solo. O trabalho utiliza um modelo conceitual, especificado num diagrama de decisão e dados levantados na pesquisa, para evidenciar a relação qualitativa e quantitativa existente entre as diferentes alternativas consideradas e as variáveis mais relevantes para caracterização do problema. O modelo definido no diagrama de decisão foi implementado em software, em planilha eletrônica, de forma a facilitar o processo de seleção das melhores alternativas para gestão do risco de granizo, a partir da situação existente com relação a preços, custos e outras informações relevantes. Esse software foi utilizado em estudo de caso realizado junto a uma cooperativa de produtores de maçã de São Joaquim, SC, para a análise quantitativa das alternativas levantadas. O trabalho visa fornecer subsídios técnicos que auxiliem os agricultores no processo de tomada de decisão quanto à estratégia mais adequada para a administração do risco de chuvas de granizo em seus pomares, auxiliem as empresas de seguro na elaboração de novos contratos em suas carteiras agrícolas e, também, o governo no desenvolvimento de novas políticas voltadas ao setor agropecuário. / The damage caused by hailstorms is one of the most important problems faced by the apple producers, in Brazil, and in other countries. This work presents, from a literature review and local surveys within the apple producing region in Santa Catarina State, Brazil, a characterization of the hail risk problem and an evaluation of existing alternatives for risk management. The alternatives considered in the risk management process included: commercial insurance, mutual insurance, spatial diversification, antihail nets, hail rockets and ground burners. Besides, the research presents a conceptual model that uses decision diagrams to describe the qualitative relationship among the different alternatives for administration of the hail risk and the most important variables for the problem. The decision diagram guided the development of a software tool designed to help the selection of the best combination of alternatives for hail risk management. This software tool, implemented in a spreadsheet, was used in a case study involving an association of apple producers in São Joaquim, SC. The intention of this work is to aid apple producers in the selection of the most appropriate strategy for the administration of the risk of hailstorms in their orchards, aid the insurance companies in the design of new contracts in your agricultural portfolio and, also, aid the government in the development of new agricultural policies.

Η Εργασιακή Ικανοποίηση αποτελεί τον συνδετικό κρίκο ανάμεσα στις θεωρίες των κινήτρων και την εφαρμογή τους στον εργασιακό χώρο και αποτελεί την πιο μελετημένη μεταβλητή στο εργασιακό γίγνεσθαι. Συνοπτικά η επαγγελματική ικανοποίηση μπορεί να περιγραφεί ως ένα σύνολο στάσεων που οι εργαζόμενοι έχουν απέναντι στη δουλειά τους, ή ως μια ψυχολογική προδιάθεση που περιλαμβάνει πολλές επιμέρους στάσεις και συναισθήματα για διάφορες όψεις της εργασίας (Schultz, 1982). Σκοπός της διατριβής είναι η εκτίμηση του βαθμού ικανοποίησης των επαγγελματιών υγείας από την εργασία τους και η ανάδειξη των παραγόντων εκείνων που την επηρεάζουν. Το δείγμα αποτελείται από 572 εργαζομένους των δημόσιων νοσοκομείων της Περιφέρειας Πελοποννήσου όλων των κατηγοριών ιατροί, νοσηλευτές, καθώς και διοικητικό, τεχνικό, βοηθητικό και παραϊατρικό προσωπικό. Τα δεδομένα συλλέχθηκαν με τη μέθοδο του δομημένου ερωτηματολογίου για την περίοδο 2006. Τα αποτελέσματα έδειξαν ότι η ηλικία και το επίπεδο εκπαίδευσης είναι οι πρωταρχικοί παράγοντες οι οποίοι επηρεάζουν την υποκειμενική αντίληψη για την ικανοποίηση των επαγγελματιών υγείας από την εργασία τους. Επιπλέον, περισσότερο συνολικά ικανοποιημένοι είναι οι άνδρες, οι εργαζόμενοι υποχρεωτικής εκπαίδευσης και το βοηθητικό προσωπικό. Μικρότερη ικανοποίηση φαίνεται να βιώνουν οι γυναίκες, οι κάτοχοι μεταπτυχιακού τίτλου και το διοικητικό και νοσηλευτικό προσωπικό. Τα θέματα τα οποία αναδεικνύονται ως μείζονος σημασίας στη διαμόρφωση του επιπέδου ικανοποίησης από την εργασία είναι (α) η αντίληψη των εργαζομένων για τον οργανισμό και τη θέση απασχόλησής του, (β) η αίσθηση επαγγελματικής επάρκειας και προσφοράς αποτελεσματικού έργου και (γ) η έλλειψη επιβράβευσης της Διοίκησης στις περιπτώσεις αποτελεσματικής απόδοσης. / --