Estimation Uncertainty in Credit Risk Assessment: Comparison of Credit Risk Using Bootstrapping and an Asymptotic Approach
Henry Dannenberg
IWH Discussion Papers,
No. 3,
2009
Abstract
For credit risk assessment, probability of default and correlation have to be estimated simultaneously. However, these estimates are uncertain. To assess this uncertainty the literature has discussed the use of asymptotic confidence regions. This kind of region though needs a long credit history for exact assessment. An alternative method to generate a confidence region for a short credit history is bootstrapping. Hence, it could be more appropriate to assess estimation uncertainty with bootstrapping than with asymptotic methods if only a short credit history is available. Based on a simulation study, it is analyzed how many periods should be available for assessing credit risk – taking account of estimation uncertainty – if bootstrapping and a Wald confidence region shall achieve similar results. This article shows that more than 100 cycles have to be available for similar results.
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The Transition to Post-industrial BMI Values Among US Children
John Komlos, Ariane Breitfelder, Marco Sunder
NBER Working Paper No. 13898,
No. 13898,
2008
Abstract
In our opinion, the trend in the BMI values of US children has not been estimated accurately. We use five models to estimate the BMI trends of non-Hispanic US-born black and white children and adolescents ages 2-19 born 1941-2006 on the basis of all NHES and NHANES data sets. We also use some historical BMI values for comparison. The increase in BMIZ values during the period considered was on average 1.3σ (95% CI: 1.16σ; 1.44σ) among black girls, 0.8σ for black boys, 0.7σ for white boys, and 0.6σ for white girls. This translates into an increase in BMI values of some 5.6, 3.3, 2.4, and 1.5 units respectively. While the increase in BMI values started among the birth cohorts of the 1940s among black females, the rate of increase tended to accelerate among all four groups born in the mid-1950s to early-1960s with the contemporaneous spread of TV viewing. The rate of increase levelled off somewhat thereafter. There is some indication that among black boys and white girls born after c. 1990 adiposity has remained unchanged or perhaps even declined. The affects of the IT revolution of the last two decades of the century is less evident. Some regional evidence leads to the speculation that the spread of automobiles and radios affected the BMI values of boys already in the interwar period. We infer that the incremental weight increases are associated with the labor-saving technological developments of the 20th century which brought about many faceted cultural and nutritional revolutions.
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Schätzunsicherheit oder Korrelation, Welche Risikokomponente sollten Unternehmen bei der Bewertung von Kreditportfoliorisiken wann berücksichtigen?
Henry Dannenberg
IWH Discussion Papers,
No. 5,
2007
Abstract
The use of probability of default estimates to assess the risks of a credit portfolio should not ignore estimation uncertainty. The latter can be quantified by confidence intervals. But assumptions about dependencies of these intervals are inconsistent with assumptions of conventional credit portfolio models. Based on simulation studies this paper shows, that a model which include estimation uncertainty but ignore default correlation might estimate the real credit risk more correctly than a model that implicates default correlation but ignore estimation uncertainty. The latter is a trait of conventional credit portfolio models. In this paper quantifying of estimation uncertainty based on the idea of confidence intervals and the underlying probability distributions of these intervals.
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Financial Openness and Business Cycle Volatility
Claudia M. Buch, Jörg Döpke, C. Pierdzioch
Journal of International Money and Finance,
No. 5,
2005
Abstract
This paper discusses whether the integration of international financial markets affects business cycle volatility. In the framework of a new open economy macro-model, we show that the link between financial openness and business cycle volatility depends on the nature of the underlying shock. Empirical evidence supports this conclusion. Our results also show that the link between business cycle volatility and financial openness has not been stable over time.
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EU Eastern Enlargement and Structural Change: Specialization Patterns in Accession Countries and Economic Dynamics in the Single Market
Albrecht Kauffmann, P. J. J. Welfens, A. Jungmittag, C. Schumann
Diskussionsbeiträge des Europäischen Instituts für Internationale Wirtschaftsbeziehungen (EIIW), Bergische Universität Wuppertal, Nr. 106,
No. 106,
2003
Abstract
This paper analyses key issues of structural change and specialization patterns in the economies of an enlarged European Union. In all transition countries we observe a shift from the agricultural and industrial sector towards the service sector in terms of employment and productivity; however, in some countries a reindustrialisation drives is observed in a late transition stage. While some countries namely the Czech Republic, Hungary, Slovakia, Poland, Estonia and Slovenia, have improved their productivity especially in medium-technology-intensive industries and may advance on the technological ladder, others remain unchanged and seem to get locked in labour-intensive industrial sectors. In the context of EU-enlargement, we expect trade creation – going along with a rise of intra-industry trade – and higher FDI-activities. Countries will have to adjust along the logic of comparative advantage, however, technological upgrading and human capital formation are fields in which government can stimulate the direction of comparative advantage. According to the Gerschenkron-hypothesis the accession countries have an “advantage of backwardness. Since accession countries have a low R&D-GDP ratio in the early transition stage rising government expenditures on research and development plus higher education is crucial. We expect the EU-15 countries in general to benefit from enlargement but gains will be asymmetric across countries: economic geography matters. Austria, Germany, the Scandinavian countries, the Netherlands, Italy and France are likely to profit more than the other members of EU-15. Germany and Austria additionally play a particularly crucial role as origins of FDI. Future research should focus on the speed and the scope of structural adjustment.
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