We consider clustering in group decision making where the opinions are given by pairwise comparison matrices. In particular, the k-medoids model is suggested to classify the matrices as it has a linear programming problem formulation. Its objective function depends on the measure of dissimilarity between the matrices but not on the weights derived from them. With one cluster, our methodology provides an alternative to the conventional aggregation procedures. It can also be used to quantify the reliability of the aggregation. The proposed theoretical framework is applied to a large-scale experimental dataset, on which it is able to automatically detect some mistakes made by the decision-makers.

Qualifications for several world championships in sports are organised such that distinct sets of teams play in their own tournament for a predetermined number of slots. This paper provides a reasonable approach to allocate the slots based on historical matches between these sets of teams. We focus on the FIFA World Cup due to the existence of an official rating system and its recent expansion to 48 teams. Our proposal extends the methodology of the FIFA World Ranking to compare the strengths of five confederations. Various allocations are presented depending on the length of the sample, the set of teams considered, as well as the frequency of rating updates. The results show that more European and South American teams should play in the FIFA World Cup. The ranking of continents by the number of deserved slots is different from the ranking implied by FIFA policy. We recommend allocating at least some slots transparently, based on historical performances, similar to the access list of the UEFA Champions League.

Chowdhury, Sutter and Zimmermann (2022) assessed the risk, time, and social preferences of family members in rural Bangladesh, presenting two main findings. First, there is a strong and positive association between family members’ preferences, even when controlling for personality traits and family background. Second, families can be grouped into two clusters: approximately 20% of the families are characterized by relatively impatient, risk-averse, and spiteful members, while the rest of the families have relatively patient, risk-tolerant, and prosocial members. Recognizing the pivotal role of cluster analysis in deriving the second result, we first successfully computationally reproduced the results, and then we conducted two types of robustness checks. The first examines the transformation of variables (continuous or categorical), affecting the proximity measure that is crucial to cluster analysis. The second assesses the effect of varying the number of clusters on the findings. Some results are robust, as we consistently find the small cluster of families identified by Chowdhury et al. (2022). However, divergent outcomes emerge with categorical variables (a logical choice given their nature) and a larger number of clusters (3 or 4). We conclude that, although the cluster analysis by Chowdhury et al. (2022) is valid, its outcomes significantly depend on the researcher’s assumptions and choices. Careful consideration of several alternatives is essential in exploratory cluster analysis to identify stable groups.

Abstract
The linguistic-savings hypothesis posits that the grammatical marking of future events in languages is linked to future-oriented behavior. Recent experimental studies have suggested patience as a possible mechanism connecting language use and future-oriented behavior by exogenously manipulating what language is used. Our paper explores the association between patience and the language that people naturally use, thereby building on endogenous (as opposed to exogenously manipulated) language use. To capture natural language usage, we utilized a novel sentence-completion task designed for native speakers of the Hungarian language. This language allows for referencing future events through both present and future tenses. We hypothesized a positive correlation between being patient and using the present tense to refer to future events. We conducted incentivized and non-incentivized experiments with four independent samples of high school and university students, involving nearly 3,500 students in total. We find no consistent evidence that patience is correlated with endogenous future-time reference. Our null finding is further supported by a robustness check that leverages specific randomness in our data.