When groups of individuals make choices among several alternatives, the most compelling social outcome is the Condorcet winner, namely the alternative beating all others in a pair-wise contest. Obviously the Condorcet winner cannot be overturned if one sub-group proposes another alternative it happens to favor. However, in some cases, and especially with haphazard voting, there will be no clear unique winner, with the outcome consisting of a triple of pair-wise winners that each beat different subsets of the alternatives (i.e. a “top-cycle”.) We explore the sensitivity of Condorcet winners to various perturbations in the voting process that lead to top-cycles. Surprisingly, variations in the number of votes for each alternative is much less important than consistency in a voter’s view of how alternatives are related. As more and more voter’s preference orderings on alternatives depart from a shared model of the domain, then unique Condorcet outcomes become increasingly unlikely.

Au cours de cette thèse, des outils théoriques (simulation) et expérimentaux (tracking) ont été développés afin d’établir les mécanismes sous-jacents aux phénomènes de choix collectifs d’exploitation de sources de nourriture et à la gestion collective des stocks de nourriture constitués au sein d’une colonie de fourmis. Le premier volet de mon travail révèle l’influence de caractéristiques physiques (telles que l’angularité et la topographie) des pistes entre le nid et les sources de nourritures, sur les comportements des fourmis au niveau individuel et leur résultante au niveau collectif en termes d’exploitation de ressources alimentaires. Le second volet de ma thèse est consacré aux dynamiques et régulations à l’œuvre au sein des phénomènes de dissémination collective et d’accumulation de nourriture au niveau intranidal. Les réseaux de distributions et d’échanges, reconstitués chez différentes espèces grâce à un marquage individuel et dans différents contextes montrent des similarités inattendues, notamment en termes d’hétérogénéités interindividuelles et de robustesse face à la variabilité des ressources. / During my PhD I have developed theoretical (simulation) and experimental (tracking) tools to investigate the mechanisms underlying the collective food source choice as well as collective food management at the intranidal level in ants. A first part of my thesis reveals the influence of the physical (and in particular the angularity and the topography) properties of the trail to the food source on the ant behavior at the individual level and its resulting food source choice/exploitation at the collective level. The second part of my thesis is dedicated to the dynamics of the food flow entering the nest, its regulation and the food dissemination/accumulation processes at the intranidal level through trophallaxis (mouth-to-mouth fluid exchange). The networks of food distributions and exchanges were built for two ant species in various experimental conditions. Interestingly, all theses networks show several similar properties, such as a high degree of heterogeneity in the individual participation to the food exchange activity as well as a robustness facing environmental variabilities.

The first chapter presents a theoretical model of electoral competition where two parties can increase campaign contributions by choosing policies benefiting a significant interest group. However, such decision will shrink their hardcore vote base where voters are well informed about the policy. The parties can then allocate the funds between campaigning and personal wealth. Different from the core voters, independent voters can be attracted by advertisements funded by campaign spending. Using a multi-stage extensive form game, I investigate how electoral competition interacts with diversions and policy distortions. My result shows that a higher level of electoral competition helps mitigate policy distortions but prompts the parties to divert more funds. Perfectly informed signal senders need to communicate their true type (productivity or ability) which is often private information to potential receivers. While tests are commonly used as measures of applicants' productivity, the accuracy of them has been questioned. Beginning with the framework of a two-type labor market signaling game, the second chapter investigates how tests of limited reliability affect the nature of equilibria in signaling games with asymmetric information. Our results show that, if a test is inaccurate and costly, only pooling PBE exists given certain conditions. Different forms of test inaccuracy may allow a separating PBE to exist. We also study the case of three types and find different PBEs. The central issue of siting noxious facilities is that the host community absorbs potential costs, while all others can share the benefits without paying as much. The third chapter presents a modified Clarke mechanism to facilitate the siting decision, taking into account all residents' strategies. Suppose that the social planner is able to reasonably estimate the possible costs, depending on the host location, to each resident created by the facility. Our proposed Clarke mechanism is characterized by strategy-proofness and yields an efficient siting outcome. The issue of budget imbalance is mitigated when the compensation scheme is fully funded with the tax revenue based on the benefits. We then use a simple example to show that a weighted version of the Clarke mechanism may yield a different outcome. / Ph. D. / People worry that lobbying may affect legislative decision-making in ways that disadvantage ordinary citizens. The first chapter presents a theoretical model of electoral competition where two parties can increase campaign contributions by choosing policies benefiting a significant interest group. However, such decision will shrink their hardcore vote base where voters are well informed about the policy. The parties can then allocate the funds between campaigning and personal wealth. Different from the core voters, independent voters can be attracted by advertisements funded by campaign spending. The result shows that a higher level of electoral competition helps mitigate policy distortions, but prompts the parties to divert more funds. Signaling games have been widely used for decades. Perfectly informed signal senders need to communicate their true type (productivity or ability) which is often private information to potential receivers. While tests are commonly used as measures of applicants’ productivity, the accuracy of them has been questioned. Beginning with the framework of a two-type labor market signaling game, the second chapter investigates how tests of limited reliability affect the nature of equilibria in signaling games with asymmetric information. Our results show that, if a test is inaccurate and costly, both high- and low-productivity workers voluntarily take the test given certain conditions. Different forms of test inaccuracy may allow the existence of a specific equilibrium where only high-productivity workers are willing to take the test. We also study the case of three types and find different types of equilibria. The central issue of siting noxious facilities is that the host community absorbs potential costs, while all others can share the benefits without paying as much. The third chapter presents a modified Clarke mechanism to facilitate the siting decision, taking into account all residents’ strategies. Suppose that a social planner is able to reasonably estimate the possible costs, depending on the host location, to each resident created by the facility. Our proposed mechanism motivates all citizens to honestly report their preferences and yields an efficient siting outcome. The issue of budget imbalance is mitigated when the total cost, including the compensation scheme, is fully funded with tax revenues. We then use a simple example to show that a wealth-weighted version of our proposed Clarke mechanism may yield a different outcome.

Cette Thèse pose la question de la décision collective sous incertitude possibiliste. On propose différents règles de décision collective qualitative et on montre que dans un contexte possibiliste, l'utilisation d'une fonction d'agrégation collective pessimiste égalitariste ne souffre pas du problème du Timing Effect. On étend ensuite les travaux de Dubois et Prade (1995, 1998) relatifs à l'axiomatisation des règles de décision qualitatives (l'utilité pessimiste) au cadre de décision collective et montre que si la décision collective comme les décisions individuelles satisfont les axiomes de Dubois et Prade ainsi que certains axiomes relatifs à la décision collective, particulièrement l'axiome de Pareto unanimité, alors l'agrégation collective égalitariste s'impose. Le tableau est ensuite complété par une axiomatisation d'un pendant optimiste de cette règle de décision collective. Le système axiomatique que nous avons développé peut être vu comme un pendant ordinal du théorème de Harsanyi (1955). Ce résultat á été démontré selon un formalisme qui et basé sur le modèle de de Von NeuMann and Morgenstern (1948) et permet de comparer des loteries possibilistes. Par ailleurs, on propose une première tentative pour la caractérisation des règles de décision collectives qualitatives selon le formalisme de Savage (1972) qui offre une représentation des décisions par des actes au lieu des loteries. De point de vue algorithmique, on considère l'optimisation des stratégies dans les arbres de décision possibilistes en utilisant les critères de décision caractérisés dans la première partie de ce travail. On offre une adaptation de l'algorithme de Programmation Dynamique pour les critères monotones et on propose un algorithme de Programmation Multi-dynamique et un algorithme de Branch and Bound pour les critères qui ne satisfont pas la monotonie. Finalement, on établit une comparaison empirique des différents algorithmes proposés. On mesure les CPU temps d'exécution qui augmentent linéairement en fonction de la taille de l'arbre mais restent abordable même pour des grands arbres. Ensuite, nous étudions le pourcentage d'exactitude de l'approximation des algorithmes exacts par Programmation Dynamique: Il apparaît que pour le critère U-max ante l'approximation de l'algorithme de Programmation Multi-dynamique n'est pas bonne. Mais, ceci n'est pas si dramatique puisque cet algorithme est polynomial (et efficace dans la pratique). Cependant, pour la règle U+min ante l'approximation par Programmation Dynamique est bonne et on peut dire qu'il devrait être possible d'éviter une énumération complète par Branch and Bound pour obtenir les stratégies optimales. / This Thesis raises the question of collective decision making under possibilistic uncertainty. We propose several collective qualitative decision rules and show that in the context of a possibilistic representation of uncertainty, the use of an egalitarian pessimistic collective utility function allows us to get rid of the Timing Effect. Making a step further, we prove that if both the agents' preferences and the collective ranking of the decisions satisfy Dubois and Prade's axioms (1995, 1998) and some additional axioms relative to collective choice, in particular Pareto unanimity, then the egalitarian collective aggregation is compulsory. The picture is then completed by the proposition and the characterization of an optimistic counterpart of this pessimistic decision rule. Our axiomatic system can be seen as an ordinal counterpart of Harsanyi's theorem (1955). We prove this result in a formalism that is based on Von NeuMann and Morgenstern framework (1948) and compares possibilisitc lotteries. Besides, we propose a first attempt to provide a characterization of collective qualitative decision rules in Savage's formalism; where decisions are represented by acts rather than by lotteries. From an algorithmic standpoint, we consider strategy optimization in possibilistic decision trees using the decision rules characterized in the first part of this work. So, we provide an adaptation of the Dynamic Programming algorithm for criteria that satisfy the property of monotonicity and propose a Multi-Dynamic programming and a Branch and Bound algorithm for those that are not monotonic. Finally, we provide an empirical comparison of the different algorithms proposed. We measure the execution CPU times that increases linearly according to the size of the tree and it remains affordable in average even for big trees. Then, we study the accuracy percentage of the approximation of the pertinent exact algorithms by Dynamic Programming: It appears that for U-max ante criterion the approximation of Multi-dynamic programming is not so good. Yet, this is not so dramatic since this algorithm is polynomial (and efficient in practice). However, for U+min ante decision rule the approximation by Dynamic Programming is good and we can say that it should be possible to avoid a full Branch and Bound enumeration to find optimal strategies.

Les fondements philosophiques de la théorie du choix social sont l’objet de cette thèse. La théorie du choix social est un champ de l’économie normative qui traite de l’agrégation des préférences individuelles. L’objectif de ce travail est d’analyser les postulations philosophiques de la théorie du choix social afin de comprendre dans quelle mesure celle-ci pourrait contribuer à une théorie de la justice sociale basée sur les capabilités d’Amartya Sen. Ce travail est par conséquent élaboré à partir de l’idée d’une « approche comparative » de la justice sociale, défendue par Amartya Sen, et que ce dernier oppose à l’ « approche transcendantale » de John Rawls. Nous tentons d’y préciser l’interprétation de la théorie du choix social requise pour spécifier l’approche par les capabilités, et en particulier l’évaluation et la construction d’un indice de capabilités et de fonctionnements. Ce travail de thèse défend l’hypothèse selon laquelle la tension apparente entre l’agrégation des préférences et l’approche par les capabilités est due à une interprétation étroite du cadre conceptuel de la théorie du choix social. En effet, l’approche par les capabilités est généralement comprise comme incompatible avec le préférentialisme de la théorie du choix social. Cela est dû à ce que l’approche par les capabilités s’est construite en partie comme une réponse au problème des préférences adaptatives. Cette thèse consiste donc à élargir le champ des interprétations de la théorie du choix social et de son cadre conceptuel, principalement de sa base d’information.La première partie de ce travail de recherche traite la question suivante : les préférences sont-elles déterminées par une source individuelle pouvant être pensée indépendamment de sa position sociale et économique ? Afin de montrer que ce n’est pas nécessairement le cas sur le plan logique, nous y analysons trois types de base informationnelle : les utilités cardinales, les préférences ordinales et les capabilités.L’objectif de la seconde partie est de déterminer ce que les préférences décrivent. Nous y analysons d’une part la nature de la préférence elle-même dans ce contexte. S’agit-il d’une décision déterminant une action, d’un désir, d’un état mental ou encore d’un jugement de valeur ? D’autre part, les différents critères éthiques de préférence sont étudiés, à savoir le plaisir hédoniste, la satisfaction des désirs et un critère de bien-être objectif. Cette exploration nous amène à défendre la conclusion suivante : la conception des préférences la plus en phase avec la structure formelle de la théorie du choix social est une conception comparative requérant d’excellentes conditions cognitives pour que les préférences puissent être considérées à proprement parler comme les véritables préférences de l’agent.La troisième partie revient à l’approche des capabilités. L’argumentation s’appuie sur les conclusions des deux parties précédentes afin de jeter les bases d’une théorie de la justice démocratique et non-idéale basée sur les capabilités d’Amartya Sen. Dans cette partie, nous montrons qu’une évaluation des capabilités indépendante des préférences tend à nier l’importance de la liberté et de la qualité d’agent dans l’approche par les capabilités. Nous défendons donc l’hypothèse selon laquelle les capabilités et les fonctionnements comme objets de préférence permettent de filtrer celles-ci afin de parer au problème des préférences adaptatives. / This dissertation examines the philosophical foundations of social choice theory. Social choice theory is the area of normative economics which is concerned with the aggregation of individual preferences. The aim of this work is to investigate the philosophical assumptions of social choice theory in order to understand to what extent it can contribute to a theory of justice based on capabilities. Therefore, the dissertation is build up on Amartya Sen’s idea of a “comparative approach” of justice, as opposed to the Rawlsian “transcendental approach”. It is an attempt to precise which understanding of social choice theory is required to specify the capability approach, especially the evaluation and the indexing of capabilities. In this dissertation, we argue that the apparent tension between preference aggregation and capability approach is due to a narrow interpretation of social choice theory’s conceptual framework. Capability approach is generally conceived as non-compatible with the preferentalism of social choice theory: after all, capabilities are seen as a response to the recurring problem of adaptive preferences. This dissertation thus consists in widening the scope of interpretations of social choice theory framework. This research deals mainly with the informational basis of social choice theory.This dissertation is in three parts. The first part tackles the following problem: are preferences determined by an individual source that can be thought independently of its social and economic position? To answer these questions, three kinds of informational basis in social choice theory and normative economics are investigated: cardinal utilities, ordinal preferences and capabilities.The second part aims at defining what preferences do describe in this context. Firstly, the nature of preference itself is examined: can it be assimilated to choice? Or is it a mere evaluation? A desire? A mental state? This analysis points out the comparative structure of preferences. Secondly, the various ethical criteria of preference are investigated: hedonistic pleasure, desire satisfaction and objective well-being. We argue that preferences are better conceived as comparative evaluation and require actually excellent cognitive conditions to be truly the agent’s own real preferences.The third part goes back to capability approach. The argument relies on the previous results to build up a first account of a democratic non-ideal theory of justice based on capabilities. In this part, we show that a preference-independent capability evaluation turns out to dismiss the importance of freedom and agency in capability approach. Then we argue that capabilities and functionings as an object for preferences do provide a first filter against adaptive preferences.

The Allee effect corresponds to a positive relationship between population size and individual fitness. This positive relationship can cause thresholds, that is, critical population sizes below which the population becomes extinct. For species submitted to the Allee effect, the formation and cohesion of groups is therefore crucial to survival. Animals can achieve this collective behaviour through local interactions. Each individual interacts locally with conspecifics and, at the scale of the group, a unity of behaviour emerges: the animals move together, rest in the same place, or choose the same habitat patch to settle on. <p><p>We use a combination of mathematical modelling and experimental work to study certain mechanisms of collective behaviour. In particular we assess the extent to which different individual interactions can induce collective patterns and thereby influence the dynamics of dispersal and settlement of populations. First, we study the collective settlement induced by the arresting effect of a marker secreted by conspecifics. Then, two potential mechanisms for collective movement are examined: following the conspecifics and following a trail laid by conspecifics. Finally, we integrate explicit mechanisms of dispersal behaviour in a dynamic model involving a set of interconnected populations. This allows the study of the interplay between collective movements and Allee effects at the scale of the metapopulation.<p><p>Our work is inspired by the lifestyle of the two-spotted spider mite, Tetranychus urticae, a phytophagous pest of recognised agricultural importance. These subsocial mites live in aggregates on the leaf surface, protected by a collectively spun silk web. Experimental evidence suggests that its population dynamics are subject to the Allee effect. Moreover, these mites show a tendency to migrate collectively, which makes them an appropriate biological model. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Cette thèse porte sur les mécanismes d’allocation de biens indivisibles en présence d’externalités dans les préférences individuelles. Ces externalités rendent difficile en pratique la collecte d’une information complète sur les préférences. Aussi, l’analyse normative des mécanismes d’allocation requiert de formuler des hypothèses sur la manière d’étendre l’information collectée aux préférences sur les allocations. Cette approche revient à définir des restrictions sur le domaine de préférences admissibles, une démarche bien connue de la théorie du choix social. Les trois premiers chapitres portent sur l’analyse du marché de Shapley-Scarf dans lequel les échanges sont organisés entre coalitions. Les chapitres 1 et 2 établissent des restrictions de domaine garantissant l’existence de différents types d’équilibre concurrentiel. Dans le chapitre 3, l’ensemble des biens est muni d’une géographie, ce qui permet de définir la distance entre partenaires comme source d’externalité. Nous identifions certains domaines de préférences qui assurent la non-vacuité de différents types de Coeur. Le chapitre 4 porte sur le cas de biens indivisibles publics purs. Nous montrons que le problème est formellement équivalent à celui du choix d’un comité dont les membres sont choisis dans des ensembles distincts. Nous caractérisons certains domaines de préférences sur les comités pour lesquels le choix majoritaire membre par membre est cohérent avec le choix majoritaire du comité dans son ensemble. / This thesis focuses on the allocation of indivisible goods in presence of externality in individual preferences. This externality creates a difficulty with collecting full information about preferences. Therefore, conducting a normative analysis of allocation mechanisms requires assumptions on how reported preferences can be extended to preferences over outcomes. This approach is in line with the literature on preference domain restriction well-known in Social Choice theory. The first three chapters focus on Shapley-Scarf markets where trades are organized among coalitions. Coalitional trade generates externalities in individual valuations of allocations. Chapters 1 and 2 investigate domain restrictions ensuring the existence of various types of competitive equilibrium. Chapter 3 endows the set of goods with a geographical structure and considers distance to partners as a source of externality in preference. We identify domains of preference extensions which guarantee the existence of various types of core allocations. Chapter 4 focuses the case of pure public indivisible goods, which is formally identical to choosing a committee formed by several members, each selected from a specific set. We characterize preference domains over committees for which a well-defined seat-wise choice procedure based on majority voting is consistent with choosing a committee at once from majority voting.

Tesis por compendio / [ES] El brote de Coronavirus SARS-CoV-2 representó un reto para la economía, la vida social y los servicios sanitarios. Justo cuando más se necesitaba la información para la planificación económica, los servicios de vigilancia y notificación no fueron capaces de ofrecer, a pesar de esfuerzos extraordinarios, datos consistentes, como así reconocieron los propios orga-nismos gubernamentales. Esta tesis incluye tres artículos publicados durante los brotes de COVID-19 y una investi-gación adicional fuera del conjunto de publicaciones. La investigación tiene como objetivo general proporcionar información a través de estimaciones alternativas. Para ello se han utilizado varias metodologías, entre ellas los modelos matemáticos de predicción epidemio-lógica, el Mejor Ajuste de Valores Relacionados (BARV), los análisis de diferentes encues-tas y la metodología bibliométrica, aprovechando u ofreciendo alternativas a los métodos bayesianos más complejos, las simulaciones de Monte Carlo o las cadenas de Markov, aun-que algunos datos obtenidos se apoyan parcialmente en estas metodologías. Cada artículo aborda un tema esencial relacionado con la pandemia COVID-19. La primera publicación se centra en los datos epidemiológicos básicos. Se refiere al primer brote de COVID-19, estimando su duración, incidencia, prevalencia, tasa de fallecimientos sobre infectados (IFR) y tasa de fallecimientos sobre casos (confirmados) (CFR). Como dato destacado de este trabajo, se previó que la seroprevalencia era demasiado baja para que la inmunidad de rebaño desempeñara algún papel. Aunque el valor obtenido fue aproxima-damente un 2% inferior al que demostró posteriormente un estudio poblacional (Instituto Carlos III), la conclusión sobre la inmunidad de rebaño no cambió, y los resultados confir-maron la idoneidad del enfoque. La segunda publicación se centró en las cuestiones legales y las noticias falsas, analizando la reticencia de la población a vacunarse, el impacto de las falsas noticas en estos comporta-mientos, las posibilidades legales de hacer obligatoria la vacuna y las posibles acciones contra los profesionales de la salud que publican noticias falsas. La principal conclusión fue que, aunque se podría encontrar una vía legal para la obligatoriedad de la vacunación, y para la persecución gubernamental de las noticias falsas, la opinión ciudadana parece prefe-rir que la administración no tome la iniciativa, por lo que se recomienda promover y fomen-tar la concienciación ciudadana. La tercera publicación presentó un modelo matemático simplificado para la estimación del coste-efectividad de la vacuna contra la COVID-19. Se actualizan los datos de dos fechas para la estimación de los costes directos para el sistema sanitario debidos a la COVID-19, computando el coste por ciudadano y por Producto Interior Bruto (PIB), así como el coste-efectividad de la vacuna. La estimó razón de coste-efectividad incremental (RCEI) para dos dosis por persona a un coste de 30 euros cada dosis (incluida la administración). Asumien-do al 70% de efectividad y con el 70% de la población vacunada resultó ser de 5.132 euros (4.926 - 5.276) por año de vida ajustado a calidad (AVAC) ganado (a 17 de febrero de 2021). Una cifra que desciende cada día de pandemia activa. Se incluyó una investigación adicional, no incorporada en el conjunto de artículos, centrada en los recursos humanos y la educación. Se analizaron los temas preocupan al personal de primera línea, es decir, a la enfermería, y cómo la pandemia ha afectado a sus publicaciones científicas, como índice de los cambios en el clima laboral que sufre este colectivo. Median-te un estudio bibliométrico comparativo entre las publicaciones de 2019 y 2020, se analizó el cambio de temas y ámbitos como reflejo del impacto del COVID-19 en el personal de enfermería. Así se comprobó que, en los ámbitos de enfermería de atención especializada, y sobre todo e / [CA] El brot de Coronavirus SARS-CoV-2 va representar un repte per a l'economia, la vida soci-al i els serveis sanitaris. Quan més es necessitava la informació per a la planificació econò-mica, malgrat esforços extraordinaris, els serveis de vigilància i notificació no van ser capa-ços d'oferir dades consistents, com així van reconèixer els mateixos organismes governa-mentals. Aquesta tesi inclou tres articles publicats durant els brots de COVID-19 i una investigació addicional fora del conjunt de publicacions. La investigació té com a objectiu general pro-porcionar informació a través d'estimacions alternatives. Per a això s'han utilitzat diverses metodologies, entre elles els models matemàtics de predicció epidemiològica, el Millor Ajust de Valors Relacionats (BARV), les anàlisis de diferents enquestes i la metodologia bibliomètrica, aprofitant o oferint opcions alternatives als mètodes bayesians més comple-xos, les simulacions de Montecarlo o les cadenes de Markov, tot i que algunes dades obtin-gudes es recolzen parcialment en aquestes metodologies. Cada article aborda un tema essen-cial relacionat amb la pandèmia COVID-19. La primera publicació se centra en les dades epidemiològiques bàsiques. Es refereix al pri-mer brot de COVID-19, calculant la seua durada, incidència, prevalença, taxa de defuncions sobre infectats (IFR) i taxa de defuncions sobre casos (confirmats) (CFR). Com a dada des-tacada d'aquest treball, es va preveure que la seroprevalença era massa baixa perquè la im-munitat de ramat exercirà algun paper. Tot i que el valor obtingut va ser aproximadament un 2% inferior al demostrat posteriorment en un estudi poblacional (Institut Carles III), la conclusió sobre la immunitat de ramat no va canviar, i els resultats van confirmar la idoneï-tat de l'enfocament. La segona publicació es va centrar en les qüestions legals i les notícies falses, analitzant la reticència de la població a vacunar-se, l'impacte de les falses notícies en aquests comporta-ments, les possibilitats legals de fer obligatòria la vacuna i les possibles accions contra els professionals de la salut que publiquen notícies falses. La principal conclusió va ser que, tot i que es podria trobar una via legal per l'obligatorietat de la vacunació, i per la persecució governamental de les notícies falses, l'opinió ciutadana sembla preferir que l'administració no prenga la iniciativa, per la qual cosa es recomana promoure i fomentar la conscienciació ciutadana. La tercera publicació va presentar un model matemàtic simplificat per a l'estimació del cost-efectivitat de la vacuna contra la COVID-19. S'actualitzen les dades de dues dates per a l'estimació dels costos directes per al sistema sanitari deguts a la COVID-19, computant el cost per ciutadà i per Producte Interior Brut (PIB), així com el cost-efectivitat de la vacuna. La va estimar raó de cost-efectivitat incremental (RCEI) per dues dosis per persona a un cost de 30 euros cada dosi (inclosa l'administració). Assumint al 70% d'efectivitat i amb el 70% de la població vacunada va resultar ser de 5.132 euros (4.926 - 5.276) per any de vida ajustat a qualitat (AVAQ) (a 17 de febrer de 2021). Una xifra que descendeix cada dia de pandèmia activa. Es va afegir una investigació addicional, no inclosa en el conjunt d'articles, centrada en els recursos humans i l'educació. Es van analitzar els temes que preocupen al personal de pri-mera línia, és a dir, a la infermeria, i com la pandèmia ha afectat les seues publicacions cien-tífiques, com a índex dels canvis en el clima laboral que pateix aquest col·lectiu. Mitjançant un estudi bibliomètric comparatiu entre les publicacions de 2019 i 2020, es va analitzar el canvi de temes i camps com a reflex de l'impacte del COVID-19 en el personal d'infermeria. Així es va comprovar que en els àmbits d'infermeria d'atenció especialitzada, i sobretot en atenció primària, els principals problemes detectat / [EN] The SARS-CoV-2 Coronavirus outbreak has posed a challenge to the economy, social life, and health services. Just when information was most needed for economic planning, moni-toring, and reporting services were unable, despite extraordinary efforts to provide con-sistent data, as government agencies themselves acknowledged. This thesis includes three articles published during the COVID-19 outbreaks and additional research outside the publication set. The overall aim of the research is to provide infor-mation through alternative estimates. Several methodologies have been used, including mathematical models for epidemiological prediction, Best Adjustment of Related Values (BARV), analyses of different surveys and bibliometric methodology, taking advantage of or offering an alternative to, more complex options such as Bayesian methods, Monte Carlo simulations or Markov chains, although some data obtained are partially supported by these methodologies. Each article addresses a key issue related to the COVID-19 pandemic. The first publication focuses on basic epidemiological data. It refers to the first outbreak of COVID-19, estimating its duration, incidence, prevalence, Infection Fatality Rate (IFR) and Case Fatality Rate (CFR). As a highlight of this work, the seroprevalence was anticipated to be too low for herd immunity to play a role. Although the value obtained was approximate-ly 2% lower than that subsequently demonstrated by a population-based study (Instituto Carlos III), the conclusion on herd immunity remained unchanged, and the results con-firmed the appropriateness of the approach. The second publication focuses on legal issues and fake news, analysing reluctance to be vaccinated in the population, the impact of fake news on these behaviours, the legal possi-bilities of making vaccination mandatory, and possible actions against health professionals who publish fake news. The main conclusion was that, although a legal avenue could be found for mandatory vaccination and for governmental prosecution of fake news, public opinion seems to prefer that the authorities do not take the initiative, therefore it recom-mends promoting and encouraging public awareness. The third publication presented a simplified mathematical model for estimating the cost-effectiveness of the COVID-19 vaccine. Data from two dates were obtained for the estimation of the direct costs to the health system due to COVID-19, computing the cost per citizen and per Gross Domestic Product (GDP), as well as the cost-effectiveness of the vaccine. The estimated incremental cost-effectiveness ratio (ICER) was calculated for two doses per person at a cost of 30 euros per dose (including administration). Assuming 70% effectiveness and with 70% of the population vaccinated, it was found to be 5,132 euros (4,926 - 5,276) per quality-adjusted life year (QALY) gained (as of 17 February 2021). The figure decreases with each day of the active pandemic. Additional research not included in the set of articles focuses on human resources and education. It analyses the concerns of frontline staff, i.e., nurses, and how the pandemic has affected their scientific publications, as an index of the changes in the work climate experienced by this group. Through a comparative bibliometric study of publications in 2019 and 2020, the change in topics and fields was analysed, as a reflection of the impact of COVID-19 on nursing staff. It was found that in the fields of specialised care nursing and above all in primary care, the main problems detected are those related to protective measures and psychological factors, while the publications of nursing staff in nursing homes showed an increase in topics related to management and organisation. Finally, some aspects of the implementation of telecommuting and distance learning have been reviewed. Some of the boosts in this field resulting from the pandemic could be very useful and remain in the future, such as the incorporation of telewo / Marco Franco, JE. (2021). What have we learned from the economic impact of the Covid-19 outbreak? Critical analysis of economic factors and recommendations for the future [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/174883 / Compendio