https://hdl.handle.net/11000/459 2026-07-14T14:34:36Z https://hdl.handle.net/11000/40192 Título : Mathematical indices for the influence of risk factors on the lethality of a disease Autor : Martínez, Ricardo; Sánchez Soriano, Joaquín Resumen : We develop a theoretical model to measure the relative relevance of different pathologies of the lethality of a disease in society. This approach allows a ranking of diseases to be determined, which can assist in establishing priorities for vaccination campaigns or prevention strategies. Among all possible measurements, we identify three families of rules that satisfy a combination of relevant properties: neutrality, irrelevance, and one of three composition concepts. One of these families includes, for instance, the Shapley value of the associated cooperative game. The other two families also include simple and intuitive indices. As an illustration, we measure the relative relevance of several pathologies in lethality due to COVID-19. 2026-07-14T08:22:08Z https://hdl.handle.net/11000/40191 Título : Measuring success in streaming platforms Autor : Gonçalves Dosantos, Juan Carlos; Martínez, Ricardo; Sánchez Soriano, Joaquín Resumen : Digital streaming platforms , including Twitch, Spotify, Netflix, Disney+, and Kindle, have emerged as major sources of entertainment with significant growth potential. Many of these platforms distribute royalties among streamers, artists, producers, or writers based on their impact. In this paper, we measure the relevance of each of these contributors to the overall success of the platform, which can play a key role in revenue allocation. We perform an axiomatic analysis to provide normative foundations for four relevance metrics: the uniform, the subscriber-uniform, the proportional, and the subscriber-proportional indicators. The last two indicators implement the so-called pro-rata and user-centric models, which are extensively applied to distribute revenues in the music streaming market. The axioms we propose formalize different principles of fairness, stability, and non-manipulability, and are tailor-made for the streaming context. We complete our analysis with a case study that measures the influence of the 19 most-followed streamers worldwide on the Twitch platform. 2026-07-14T08:21:05Z https://hdl.handle.net/11000/40190 Título : The museum pass problem with consortia Autor : Gonçalves Dosantos, Juan Carlos; Martínez, Ricardo; Sánchez Soriano, Joaquín Resumen : In this paper, we extend the museum pass problem to incorporate the market structure. To be more precise, we consider that museums are organized into several pass programs or consortia. Within this framework, we propose four allocation mechanisms based on the market structure and the principles of proportionality and egalitarianism. Each mechanism satisfies a distinct set of reasonable properties related to fairness and stability, which serve to axiomatically characterize them. 2026-07-14T08:20:22Z https://hdl.handle.net/11000/40189 Título : Benchmarking Analysis of the Accuracy of Classification Methods Related to Entropy Autor : Orenes, Yolanda; Rabasa, Alejandro; Rodríguez Sala, Jesús Javier; Sánchez Soriano, Joaquín Resumen : In the machine learning literature we can find numerous methods to solve classification problems. We propose two new performance measures to analyze such methods. These measures are defined by using the concept of proportional reduction of classification error with respect to three benchmark classifiers, the random and two intuitive classifiers which are based on how a non-expert person could realize classification simply by applying a frequentist approach. We show that these three simple methods are closely related to different aspects of the entropy of the dataset. Therefore, these measures account somewhat for entropy in the dataset when evaluating the performance of classifiers. This allows us to measure the improvement in the classification results compared to simple methods, and at the same time how entropy affects classification capacity. To illustrate how these new performance measures can be used to analyze classifiers taking into account the entropy of the dataset, we carry out an intensive experiment in which we use the well-known J48 algorithm, and a UCI repository dataset on which we have previously selected a subset of the most relevant attributes. Then we carry out an extensive experiment in which we consider four heuristic classifiers, and 11 datasets. 2026-07-14T08:19:39Z https://hdl.handle.net/11000/40188 Título : The game of agents in transportation problems Autor : Aparicio Baeza, Juan; Gonçalves Dosantos, Juan Carlos; Sánchez Soriano, Joaquín Resumen : This paper deals with the analysis of the structure of the core of the transportation game (a kind of many-to-many assignment market) by means of the well known assignment game (a kind of one-to-one assignment market). To do this, we associate an allocation game to each transport game that we call the agents game. This game is obtained by means of the division of each seller and buyer into as many agents as objects they want to sell or to buy, respectively. Specifically, the relationships that exist between the core of the transportation game and the core of the agents game are analyzed. This analysis contributes to having a better knowledge about the structure of the core of the transportation game whose complete characterization continues to be an open problem. Likewise, as a result of this analysis, a new characterization of the structure of the core of the assignment game is obtained under certain conditions. 2026-07-14T08:18:41Z https://hdl.handle.net/11000/40187 Título : Order preservation with dummies in the museum pass problem Autor : Martínez, Ricardo; Sánchez Soriano, Joaquín Resumen : We study the problem of sharing the revenue obtained by selling museum passes from the axiomatic perspective. In this setting, we propose replacing the usual dummy axiom with a milder requirement: order preservation with dummies. This new axiom formalizes the philosophical idea that even null agents/museums may have the right to receive a minimum allocation in a sharing situation. By replacing dummy with order preservation with dummies, we characterize several families of rules, which are convex combinations of the uniform and Shapley approaches. Our findings generalize several existing results in the literature. Also, we consider a domain of problems that is richer than the domain proposed by Ginsburgh and Zang (Games and Economic Behavior 43:322–355, 2003) in their seminal paper on the museum pass problem. 2026-07-14T08:17:31Z https://hdl.handle.net/11000/39748 Título : Gradient tree boosting and the estimation of production frontiers Autor : Guillén García, María Dolores; Aparicio Baeza, Juan; Esteve, Miriam Resumen : In production theory and engineering, a topic of interest is the determination of technical efficiency of firms from the estimation of a technology. By definition, a technology must satisfy a set of micro-economic postulates. Likewise, a valid estimator of a technology should meet the same set of axioms. In this paper, for the first time, we adapt the Gradient Tree Boosting algorithm with the objective of estimating production technologies, satisfying the required theoretical conditions. The new approach shares similarities with the standard Free Disposal Hull (FDH) methodology, but with the advantage that it avoids the typical problem of overfitting. Finally, the performance of the new approach based on boosting is measured through a computational experience, determining that the technique based upon boosting decreases the mean squared error by more than 35% with respect to FDH. 2026-04-15T08:45:43Z https://hdl.handle.net/11000/39747 Título : Measuring dynamic inefficiency through machine learning techniques Autor : Aparicio Baeza, Juan; Esteve, Miriam; Kapelko, Magdalena Resumen : This paper contributes by developing new models for assessing dynamic inefficiency that incorporate machine learning techniques. In particular, the new approaches apply decision trees models for the estimation of dynamic production technologies that account for investment adjustment costs. Methodologically, the new models build on the recently developed techniques of Efficiency Analysis Trees (EAT) and Convexified Efficiency Analysis Trees (CEAT) and extend them even further to a dynamic framework comprising dynamic EAT and CEAT models. The study compares dynamic inefficiency scores estimated assuming the new models against the traditional dynamic free disposal hull (FDH) and dynamic data envelopment analysis (DEA). Our empirical application focuses on dairy manufacturing firms in the main dairy processing countries in the European Union for the years 2014 and 2018. The results show that inefficiency related to the dynamic CEAT or EAT is higher than their corresponding values calculated through the dynamic DEA or FDH. The discriminating power of dynamic DEA (dynamic FDH) drastically improves when switching to dynamic CEAT (dynamic EAT). Finally, the differences between countries are observed regarding the development of dynamic inefficiency in the period associated with milk quota abolition. 2026-04-15T08:44:58Z https://hdl.handle.net/11000/39746 Título : Enhancing the measurement of firm inefficiency accounting for corporate social responsibility: A dynamic data envelopment analysis fuzzy approach Autor : Aparicio Baeza, Juan; Kapelko, Magdalena; Ortiz Henarejos, Lidia Resumen : This paper contributes to research on the corporate social responsibility (CSR) field and the inefficiency measurement of firms by proposing a new method for evaluating inefficiency accounting for firms’ CSR activities. The new approach considers the imprecise nature of CSR data through the fuzzy data envelopment analysis (FDEA) method and further extends it by allowing for the dynamic interdependence of firms’ production decisions through adjustment costs, related to firms investments. In addition, the new method deals with zero or negative values for inputs and/or outputs of the data. The empirical application used in this paper considers a dataset of CSR activities of European firms for three industries (capital, consumption, and other) over the period 2014–2016. Two main results are found with this data. First, the study shows that fuzzy dynamic inefficiencies tend to be lower than these obtained from the conventional crisp evaluation of inefficiency. Second, the study finds some differences in dynamic inefficiencies at distinct levels of fuzziness. Overall, the results seem to confirm that the usage of dynamic fuzzy methodology adds some value to the standard crisp approach. 2026-04-15T08:44:01Z https://hdl.handle.net/11000/39745 Título : The standard total factor productivity index and its decomposition Autor : Aparicio Baeza, Juan; Santín González, Daniel Resumen : The Malmquist productivity index is one of the best known and most widely used measures in the economic literature to quantify and decompose changes in productivity of multi-input multi-output production processes over time. Two main approaches are used to calculate this index: the adjacent Malmquist index and the base period Malmquist index. No base period is required to calculate the adjacent Malmquist index, but it fails to comply with the circularity property. The base period Malmquist index uses the technology of a base period and is circular, but the base period choice is arbitrary. There is, therefore, a trade-off between the choice of one or another version of the Malmquist index. The aim of this paper is to introduce a new total factor productivity index that is simultaneously circular and does not need to resort to a base period or ad hoc reference. To this end, we propose a new multi-input multi-output reference production technology for use as a standard for measuring and decomposing total factor productivity changes. The standard production technology is conceptually attractive because its parameterization is versatile and adaptable to the evolution of a set of firms performing any multi-input multi-output production process. Additionally, the new approach can bring about a true total factor productivity index, which can be decomposed into an output change and an input change. 2026-04-15T08:41:43Z