Identifiability and estimation of the sign of a covariate effect in the competing risks model.

It is well known that the competing risks model is identified if the dependence structure between risks (the copula function) is known or assumed. Special cases include independence of risks or independent censoring. If the copula function is not specified, parameters of interest are only set identified. As these sets are often wide in applications, it is difficult to obtain informative results. In this paper we strike a balance between imposing too much and too little structure. By establishing a general link between observable changes in subdistributions (cumulative incidence curves) and the sign of changes in marginal distributions (the causal treatment effect) we are able to show the identifiability of the latter if the copula function is independent of the varying covariate. This has two important implications: First, it is possible to obtain informative results even if the copula function is mainly unspecified or unknown. Second, the sign of the covariate effect tends to be invariant with respect to the chosen dependence structure. Our method is computationally very simple and our simulations suggest that it identifies and consistently estimates the sign of the treatment effect for large sets of duration times. An application to unemployment duration data illustrates the usefulness of our method for empirical research.dependent censoring, nonparametric estimation, bootstrap

A Regression Model for the Copula Graphic Estimator

We consider a dependent competing risks model with many risks and many covariates. We show identifiability of the marginal distributions of latent variables for a given dependence structure. Instead of directly estimating these distributions, we suggest a plug-in regression framework for the Copula-Graphic estimator which utilises a consistent estimator for the cumulative incidence curves. Our model is an attractive empirical approach as it does not require knowledge of the marginal distributions which are typically unknown in applications. We illustrate the applicability of our approach with the help of a parametric unemployment duration model with an unknown dependence structure. We construct identification bounds for the marginal distributions and partial effects in response to covariate changes. The bounds for the partial effects are surprisingly tight and often reveal the direction of the covariate effect.Archimedean copula, dependent censoring

A copula model for dependent competing risks

Many popular estimators for duration models require independent competing risks or independent censoring. In contrast, copula based estimators are also consistent in presence of dependent competing risks. In this paper we suggest a computationally convenient extension of the Copula Graphic Estimator (Zheng and Klein, 1995) to a model with more than two dependent competing risks. We analyse the applicability of this estimator by means of simulations and real world unemployment duration data from Germany. We obtain evidence that our estimator yields nice results if the dependence structure is known and that it is a powerful tool for the assessment of the relevance of (in-)dependence assumptions in applied duration research.Archimedean copula, dependent censoring, unemployment duration

A copula model for dependent competing risks

"Many popular estimators for duration models require independent competing risks or independent censoring. In contrast, copula based estimators are also consistent in presence of dependent competing risks. In this paper we suggest a computationally convenient extension of the Copula Graphic Estimator (Zheng and Klein, 1995) to a model with more than two dependent competing risks. We analyse the applicability of this estimator by means of simulations and real world unemployment duration data from Germany. We obtain evidence that our estimator yields nice results if the dependence structure is known and that it is a powerful tool for the assessment of the relevance of (in-)dependence assumptions in applied duration research." (Author's abstract, IAB-Doku) ((en)) Additional Information Appendix for the FDZ-Methodenreport No. 02/2009Risikoabschätzung - Modell, Wirkungsforschung - Methode, Methodologie, Arbeitsmarktpolitik - Erfolgskontrolle, ältere Arbeitnehmer, Leistungsanspruch - Dauer, Arbeitslosigkeitsdauer, IAB-Beschäftigtenstichprobe

Bounds analysis of competing risks : a nonparametric evaluation of the effect of unemployment benefits on migration in Germany

"In this paper we derive nonparametric bounds for the cumulative incidence curve within a competing risks model with partly identified interval data. As an advantage over earlier attempts our approach also gives valid results in case of dependent competing risks. We apply our framework to empirically evaluate the effect of unemployment benefits on observed migration of unemployed workers in Germany. Our findings weakly indicate that reducing the entitlement length for unemployment benefits increases migration among high-skilled individuals." (Author's abstract, IAB-Doku) ((en))Arbeitslosenunterstützung, Leistungsanspruch - Dauer, Binnenwanderung, regionale Mobilität, Wanderungsmotivation, Mobilitätsbereitschaft, Arbeitslose, Hochqualifizierte, IAB-Beschäftigtenstichprobe

Bounds Analysis of Competing Risks: A Nonparametric Evaluation of the Effect of Unemployment Benefits on Imigration in Germany

In this paper we derive nonparametric bounds for the cumulative incidence curve within a competing risks model with partly identified interval data. As an advantage over earlier attempts our approach also gives valid results in case of dependent competing risks. We apply our framework to empirically evaluate the effect of unemployment benefits on observed migration of unemployed workers in Germany. Our findings weakly indicate that reducing the entitlement length for unemployment benefits increases migration among high-skilled individuals. --cumulative incidence curve,partially missing data,bounds analysis,difference-in-differences

Bounds analysis of competing risks : a nonparametric evaluation of the effect of unemployment benefits on migration in Germany (Revised version of the FDZ Methodenbericht No. 04/2007)

"This paper suggests an approach for analyzing a dependent competing risks model in presence of partly identified interval data. We apply our nonparametric bounds framework to empirically evaluate the effect of unemployment benefits on the cumulative incidence of local job finding and inter-regional migration of unemployed workers in Germany. Our findings indicate that reducing the entitlement length for unemployment benefits has heterogenous effects depending on the household composition and the wage replacement ratio in absence of unemployment benefits." (Author's abstract, IAB-Doku) ((en))Arbeitslosenunterstützung, Leistungsanspruch - Dauer, Binnenwanderung, regionale Mobilität, Wanderungsmotivation, Mobilitätsbereitschaft, Arbeitslose, Hochqualifizierte, IAB-Beschäftigtenstichprobe

Opinion: A new approach to financial regulation

It has been five years since the US Congress enacted the landmark Dodd–Frank Wall Street Reform and Consumer Protection Act; and despite the fact that about 20% of the Act has yet to be implemented (1), several legislative initiatives are now attempting to soften or roll back key provisions. This pattern of regulatory action and reaction is not new. The financial excesses of one period often lead to asset bubbles that burst, ushering in a new period of much greater regulation. This, in turn, is systematically weakened over time as markets recover and we forget the reasons why we imposed such stringent regulations in the first place. Even before Dodd–Frank, the financial industry was among the most highly regulated of industries in the world. However, the many layers of regulation and multiple regulatory agencies were insufficient to prevent financial crisis. Why

Cycle decompositions in k-uniform hypergraphs

We show that k-uniform hypergraphs on n vertices whose codegree is at least (2/3+o(1))n can be decomposed into tight cycles, subject to the trivial divisibility conditions. As a corollary, we show those graphs contain tight Euler tours as well. In passing, we also investigate decompositions into tight paths.In addition, we also prove an alternative condition for building absorbers for edge-decompositions of arbitrary k-uniform hypergraphs, which should be of independent interest

Cycle decompositions in k-uniform hypergraphs

We show that k-uniform hypergraphs on n vertices whose codegree is at least (2/3+o(1))n can be decomposed into tight cycles, subject to the trivial divisibility conditions. As a corollary, we show those graphs contain tight Euler tours as well. In passing, we also investigate decompositions into tight paths.In addition, we also prove an alternative condition for building absorbers for edge-decompositions of arbitrary k-uniform hypergraphs, which should be of independent interest