Tilburg University

About: Tilburg University is a education organization based out in Tilburg, Noord-Brabant, Netherlands. It is known for research contribution in the topics: Population & Context (language use). The organization has 5550 authors who have published 22330 publications receiving 791335 citations.

The multiple propensity score as control for bias in the comparison of more than two treatment arms: An introduction from a case study in mental health.

Abstract: Background and Objective: The propensity score method (PS) has proven to be an effective tool to reduce bias in nonrandomized studies, especially when the number of (potential) confounders is large and dimensionality problems arise. The PS method introduced by Rosenbaum and Rubin is described in detail for studies with 2 treatment options. Since in clinical practice we are often interested in the comparison of multiple interventions, there was a need to extend the PS method to multiple treatments. It has been shown that in theory a multiple PS method is possible. So far, its practical application is rare and a practical introduction lacking. Methods: A practical guideline to illustrate the use of the multiple PS method is provided with data from a mental health study. The multiple PS is estimated with a multinomial logistic regression analysis. The multiple PS is the probability of assignment to each treatment category. Subsequently, to estimate the treatment effects while controlling for initial differences, the multiple PSs, calculated for each treatment category, are included as extra predictors in the regression analysis. Results: With the multiple PS method, balance was achieved in all relevant pretreatment variables. The corrected estimated treatment effects were somewhat different from the results without control for initial differences. Conclusions: Our results indicate that the multiple PS method is a feasible method to adjust for observed pretreatment differences in nonrandomized studies where the number of pretreatment differences is large and multiple treatments are compared.

Market Size Matters

Abstract: This paper characterizes the effects of market size on the size distribution of establishments for thirteen retail trade industries across 225 U.S. cities. In most industries we examine, establishments are larger in larger cities. Models of large-group competition in which markups fall after adding competitors can reproduce this observation.

Games with permission structures : The conjunctive approach

Abstract: This paper is devoted to the game theoretic analysis of decision situations, in which the players have veto power over the actions undertaken by certain other players. We give a full characterization of the dividends in these games with a permission structure. We find that the collection of these games forms a subspace of the vector space of all games with side payments on a specified player set. Two applications of these results are provided. The first one deals with the projection of additive games on a permission structure. It is shown that the Shapley value of these projected games can be interpreted as an index that measures the power of the players in the permission structure. The second application applies the derived results on games, where the organization structure can be analysed separately from the production capacities of the participating players.

Maternal thyroid peroxidase antibodies during pregnancy: a marker of impaired child development?

Abstract: Women with antibodies against the enzyme thyroid peroxidase [TPO-Ab; formerly microsomal antibodies (MsAb)] are at particular risk for developing postpartum thyroid dysfunction; the latter is significantly associated with postpartum depression. Although the negative effect of postpartum maternal depression on child development is well documented, the consequences of elevated titers of TPO-Ab during pregnancy and subsequent postpartum thyroid dysfunction on child development are not known. In a prospective study of a cohort of 293 pregnant women, the occurrence of TPO-Ab during gestation, thyroid dysfunction, and depression was investigated. Five years after delivery, child development was assessed in 230 children of the original cohort using the Dutch translation of the McCarthy Scales of Children's Abilities. Children of women with TPO-Ab during late gestation (n = 19, with normal thyroid function) had significantly lower scores (by t test) on the McCarthy Scales of Children's Abilities than antibody-neg...

Are cultural dimensions relevant for explaining cross-national differences in antibiotic use in Europe?

Abstract: Background Antibiotics are widely-used medicines for which a more prudent use has been advocated to minimize development of resistance. There are considerable cross-national differences that can only partially be explained by epidemiological difference and variations in health care structure. The aim of this study was to explore whether cross-national differences in use of antibiotics (prescribed and non-prescribed) are associated with differences between national cultures as described in Hofstede's model of cultural dimensions (Power Distance, Individualism, Masculinity, Uncertainty Avoidance and Long-Term Orientation).