Is there a Superior Distance Function for Matching in Small Samples?
Eva Dettmann, Claudia Becker, Christian Schmeißer
Abstract
The study contributes to the development of ’standards’ for the application of matching algorithms in empirical evaluation studies. The focus is on the first step of the matching procedure, the choice of an appropriate distance function. Supplementary o most former studies, the simulation is strongly based on empirical evaluation ituations. This reality orientation induces the focus on small samples. Furthermore, ariables with different scale levels must be considered explicitly in the matching rocess. The choice of the analysed distance functions is determined by the results of former theoretical studies and recommendations in the empirical literature. Thus, in the simulation, two balancing scores (the propensity score and the index score) and the Mahalanobis distance are considered. Additionally, aggregated statistical distance functions not yet used for empirical evaluation are included. The matching outcomes are compared using non-parametrical scale-specific tests for identical distributions of the characteristics in the treatment and the control groups. The simulation results show that, in small samples, aggregated statistical distance functions are the better
choice for summarising similarities in differently scaled variables compared to the
commonly used measures.
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The Identification of Regional Industrial Clusters Using Qualitative Input-Output Analysis
Mirko Titze, Matthias Brachert, Alexander Kubis
IWH Discussion Papers,
No. 13,
2008
Abstract
The ‘cluster theory’ has become one of the main concepts promoting regional competitiveness, innovation, and growth. As most studies focus on measures of concentration of one industrial branch in order to identify regional clusters, the appropriate analysis of specific vertical relations within a value-adding chain is developing in this discussion. This paper tries to identify interrelated sectors via national input-output tables with the help of Minimal Flow Analysis by Schnabl (1994). The regionalization of these national industry templates is carried out with the allocation of branch-specific production values on regional employment. As a result, the paper shows concentrations of vertical clusters in only 27 of 439 German NUTS-3 regions.
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Alterung und technologisches Innovationspotential : Eine Linked-Employer-Employee-Analyse
Lutz Schneider
IWH Discussion Papers,
No. 2,
2007
Abstract
Growth in advanced economies is essentially driven by innovation activities. From a demographic point of view the question rises, whether the trend of an ageing workforce will affect the innovation capacities of these economies. To answer this question, the paper examines on the basis of a German linked-employer-employee-dataset, whether an older workforce lowers a firm’s potential to generate product innovations. The empirical approach is based on an Ordered-logit regression model, relating a firm’s innovation potential to the age composition of its employees. The analysis provides evidence of significant age effects. The estimated age-innovation-profile follows an inverted-ushaped pattern, it peaks at the age of about 40 years. A separate estimation shows, that the technician’s and engineer’s age seems to be particularly relevant.
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A glimpse on sectoral convergence of productivity levels
Gerald Müller
IWH Discussion Papers,
No. 133,
2001
Abstract
This paper examines the presence of sectoral convergence of labor productivity between 14 OECD countries. Using the OECD International Sectoral Data Base (ISDB), the paper looks at the developments within 12 distinct sectors during the period 1970-1995. The change of the coefficients of variance suggests that there is strong sectoral convergence within most service sectors while the evidence of convergence for Manufacturing as well as for Communication is rather weak. These findings are in line with most studies undertaken on this subject so far. It is concluded that economic theories at hand to explain growth and convergence (or divergence respectively) are of different importance for the sectors concerned. While models of the New Growth Theory seemed to be useful to explain growth mechanisms within Manufacturing and Communication, traditional models seemed to apply to most other sectors.
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Spillover effects and R&D co-operations - The influence of market structure
Anita Wölfl
IWH Discussion Papers,
No. 122,
2000
Abstract
This paper examines empirically the role of market structure for the influence of spill-over effects on R&D-cooperations. The results of a microeconometric analysis, based on firm data on innovation, let in general presume that with intensified competition also the influence of spillovers on R&D-cooperation increases. However, competition seems to induce firms to search for effective firm-specific appropriation facilities first. Spillovers that are sufficiently high such that the internalisation effect from R&D-cooperation more than outweighs the competitive effect from research, only arise whenever firms are not able to protect their research results through any appropriation facility. Additionally, there is some evidence that spillover effects may even hinder firms from cooperating in R&D when there is intensive competition on the research stage.
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