On Pearson's X^2 for categorical response variables

In this talk I discuss Pearson's X2 as a measure of goodness of fit for quantal response models, including binary outcome models (logit, probit, gompit), multinomial logistic regression (mlogit) and conditional logistic regression (clogit). Large sample results for X2 have been derived by a.o. McCullagh and Windmeijer. A Stata implementation of the test will be illustrated.

Testing for omitted variables

Testing for omitted variables should play an important part in specification analyses of statistical "linear form" models. Such omissions may comprise terms in variables that were included themselves (e.g., a quadratic term, or a categorical specification instead of a metric one), interactions between variables in the model, and variables that were left out to begin with. Re-estimating models with additional variables and performing (for example) likelihood ratio tests is time-consuming. Score tests provide an attractive alternative, since the tests can be computed using only results from the model already estimated. We present a Stata command for performing score testing after most Stata estimation commands (e.g., logit, heckman, streg etc.). This command supports multiple-equation models, clustered observations, and adjusted p-values for simultaneous testing.

The Power of the Presidency in EU Council Decision-making

Research on the presidency of the EU shows mixed results. Although most scholars agree that the EU presidency is not able to advance its domestic interests in the European forum, Tallberg (2006) provides evidence for presidency effects. In the present paper, we empirically estimate presidency-based power in the Council of the European Union on the DEU data — a large-scale data set containing EU policy issues from various policy areas. We show that holding the presidency does significantly and positively contribute to the bargaining power of member states, but only in the final stages of decision-making

Prejudice towards Muslims in The Netherlands:Testing integrated threat theory

This study uses integrated threat theory to examine Dutch adolescents’ (N ¼ 1; 187) prejudice towards Muslim minorities. One out of two participants was found to have negative feelings towards Muslims. Perceived symbolic and realistic threat and negative stereotypes were examined as mediators between antecedent factors (in-group identification, intergroup contact, and the endorsement of multiculturalism) and prejudice. Based on structural equation modelling, it was found that stereotypes and symbolic threats, but not realistic threats, predicted prejudice towards Muslims. Further, it was found that the effect of in-group identification on prejudice was fully mediated by symbolic threat, the effect of contact was partially mediated by stereotypes, and the effect of the endorsement of multiculturalism was mediated by both symbolic threat and stereotypes. In addition, contact and multiculturalism were directly associated with prejudice towards Muslims. The theoretical and practical implications of these findings are discussed.

Zur Dynamik prosozialen Verhaltens in einem asymmetrischen sozialen Dilemma: ein Beitrag zur experimentellen Spieltheorie

This contribution examines pro-social behavior in social support relations. Such relations are modeled as an asymmetric and repeated social dilemma game in which two actors can provide support for each other. We allow for asymmetry in three dimensions: (1) benefits from receiving support, (2) costs of providing support, and (3) the likelihood of needing support. Theoretically and empirically, we analyze the effects of asymmetry on the dynamics of support. We assume that the costs of providing and the benefits of receiving support as well as the likelihood of needing support affect an actor's willingness to provide support. Using a behavioral game theory approach, we contribute to theory formation by developing a simple adaptive model for explaining behavior in support relations. More precisely, we offer two variants of such an adaptive model. One variant is inspired by social psychology and implements assumptions from equity theory. The other variant is inspired by bargaining theory and uses the Kalai-Smorodinsky bargaining solution. Our model is robust in the sense that both variants lead to similar predictions. Data from laboratory experiments confirm these predictions.In diesem Beitrag untersuchen wir prosoziales Verhalten im Sinne wechselseitiger Hilfeleistungen. Als formales Modell verwenden wir ein asymmetrisches wiederholtes Solidaritätsspiel zwischen zwei Akteuren. Wir modellieren Asymmetrie in drei Dimensionen: (1.) Nutzen, den ein Akteur aus der Hilfeleistung des anderen zieht, (2.) Kosten der eigenen Hilfeleistung und (3.)Wahrscheinlichkeit, mit der ein Akteur Hilfe benötigt. Wir untersuchen die Effekte von Asymmetrie auf die Dynamik wechselseitiger Hilfeleistungen im Verlauf des Spiels. Wir nehmen an, dass die Häufigkeit, mit der sich die Akteure helfen, vom Nutzen und den Kosten der Hilfeleistungen sowie von der Wahrscheinlichkeit abhängt, Hilfe zu benötigen. Unser Beitrag zur Theoriebildung ist ein einfaches adaptives Verhaltensmodell für die Erklärung wechselseitiger Hilfeleistungen, das an das Forschungsprogramm der experimentellen Spieltheorie („behavioral game theory“) anschließt. Wir präsentieren zwei Varianten eines solchen Modells: eine sozialpsychologisch inspirierte Variante und eine Variante, die auf spieltheoretischen Verhandlungsmodellen beruht. Unser Modell ist robust in dem Sinn, dass beide Varianten zu ähnlichen Vorhersagen führen. Empirische Daten aus zwei Laborexperimenten bestätigen diese Vorhersagen

Inequality and Procedural Justice in Social Dilemmas

This study investigates the influence of resource inequality and the fairness of the allocation procedure of unequal resources on cooperative behavior in social dilemmas. We propose a simple formal behavioral model that incorporates conflicting selfish and social motivations. This model allows us to predict how inequality influences cooperative behavior. Allocation of resources is manipulated by three treatments that vary in terms of procedural justice: allocating resources randomly, based on merit, and based on ascription. As predicted, procedural justice influences cooperation significantly. Moreover, gender is found to be an important factor interacting with the association between procedural justice and cooperative behavior.