Irene Bertschek

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Discussion Papers are intended to make results of ZEW research promptly available to other economists in order to encourage discussion and suggestions for revisions. The authors are solely responsible for the contents which do not necessarily represent the opinion of the ZEW. The fast technological development of the Internet as well as the declining prices(More)
Discussion Papers are intended to make results of ZEW research promptly available to other economists in order to encourage discussion and suggestions for revisions. The authors are solely responsible for the contents which do not necessarily represent the opinion of the ZEW. Abstract: This paper analyzes the relationship between investment in information(More)
In order to assess the productivity effects of information and communication technologies (ICT), regressions based on cross–sectional firm–level data may yield unreliable results for the commonly employed production function framework. In this paper, various estimation biases and econometric strategies to overcome their sources are discussed. The effects(More)
Does online availability boost citations? Using a panel of citations to economics and business journals, we show that the enormous effects found in previous studies were an artifact of their failure to control for article quality, disappearing once fixed effects are added as controls. The absence of aggregate effects masks heterogeneity across platforms:(More)
The paper provides empirical evidence for the question whether firms' ITenabled labour productivity is affected by the age structure of the workforce. We apply a production function approach with heterogenous labour to firmlevel data from German manufacturing and services industries. We find that workers older than 49 are not significantly less productive(More)
Discussion Papers are intended to make results of ZEW research promptly available to other economists in order to encourage discussion and suggestions for revisions. The authors are solely responsible for the contents which do not necessarily represent the opinion of the ZEW. Das Papier entstand im Rahmen des Forschungsprojekts " Informationstechnologien,(More)
The generalised method of moments (GMM) is combined with the nonparametric estimation of the instrument matrix to obtain an easily computable estimator for the panel probit model. It is based on the speciication of the conditional mean of the binary dependent variable in each period, and therefore high-dimensional numerical integrations are avoided. An(More)
The paper analyses the relationship between labour productivity, the proportion of older employees and IT intensity in firms. Using firm-level data from German manufacturing and services industries, we find that workers older than 49 are not significantly less productive than prime age workers, whereas workers younger than 30 are significantly less(More)
Download this ZEW Discussion Paper from our ftp server: Numerous empirical studies at different levels of aggregation demonstrate the important role of information and communication technologies (ICT) for economic performance. As general purpose technologies ICT enable firms to reshape their business processes and to improve their products and services.(More)
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