Correlation in corporate defaults: Contagion or conditional independence?

We revisit a method used by Das et al. (2007) (DDKS) who jointly test and reject a specification of firm default intensities and the doubly stochastic assumption in intensity models of default. The method relies on a time change result for counting processes. With an almost identical set of default histories recorded by Moody’s in the period from 1982 to 2006, but using a different specification of the default intensity, we cannot reject the tests based on time change used in DDKS. We then note that the method proposed by DDKS is mainly a misspecification test in that it has very limited power in detecting violations of the doubly stochastic assumption. For example, it will not detect contagion which spreads through the explanatory variables “covariates” that determine the default intensities of individual firms. Therefore, we perform a different test using a Hawkes process alternative to see if firm-specific variables are affected by occurrences of defaults, but find no evidence of default contagion.     

Regulations for the Eighth International Congress of Actuaries

Abstract

The present paper proposes and investigates a procedure for numerical evaluation of the transition probabilities for a time-inhomogeneous Markov process when the intensities are known (estimated). The procedure is based on Taylor-expansion of the transition probabilities linked with the Chapman-Kolmogorov equations.     

Evaluating transport user benefits and social surplus in a transport market—The case of the Norwegian ferries

The article first infers how consumer surplus in a market is linked to revenue under different assumptions about fare elasticity and when using different types of demand functions. This information is added to producer surplus in order to derive social surplus. The method, thus, produces a simple approach for authorities to assess social surplus in a market and its benefits to the users. A modified exponential demand function is applied to calculate consumer surplus and social surplus for 97 ferry services in Norway regulated by the state. The calculations are based on empirical data concerning ferry fare, revenue data at service level and reasonable assumptions about fare point elasticity for services covering different distances.In 2007, these services generated welfare for the users (consumer surplus) and the society (social surplus) amounting to about 5.8 billion NOK and 4.3 billion NOK, respectively. Consumer surplus and social surplus varied considerably amongst the services. Only 3 of the 97 services operate with positive profits and, hence, without subsidies. About 21 of the services contribute negatively to social surplus. Many of these unprofitable services are the only transport alternatives in rural areas and could be argued to continue operation according to politically decided regional measures. Implicitly, maintaining all these 21 services means that the welfare for the people in these areas is valued as up to four times greater than the welfare of the people in the rest of society.     

Modelling purchases as a function of advertising and promotion

This article describes the preliminary studies of the effect of advertising and promotion on purchases. The British single-source database Adlab has been the basis for this study of advertising and promotion effectiveness. The ST AS measure and logit modelling have been used to estimate the effect of advertising. The results from the two measures have been compared to determine the extent to which the two measures give occasion for the same conclusions. To indicate the accuracy of the two measures, their respective levels of significance have been studied. Two logit models have been estimated; one only includes the effect of TV exposure, while the other also includes the effect of promotions. The results from the two logit models are compared to determine which model gives the most accurate estimate of the effect of advertising. When comparing the results from the STAS measure with the parameter estimates from the second logit model, it is found that these two different measures largely lead to similar conclusions. Suggestions for further research and developments of the models are given.     

Estimating the natural rates in a simple New Keynesian framework

The time-varying natural rate of interest and output and the implied medium-term inflation target for the US economy are estimated over the period 1983–2005. The estimation is conducted within the New Keynesian framework using Bayesian and Kalman-filter estimation techniques. With the model-consistent estimate of the output gap, we get a small weight on the backward-looking component of the New Keynesian Phillips curve—similar to what is obtained in studies which use labor share of income as a driver for inflation (e.g., Galí, Eur Econ Rev 45(7):1237–1270, 2001; Eur Econ Rev 47(4):759–760, 2003). The turning points of the business cycle are nevertheless broadly consistent with those of CBO/NBER. We find considerable variation in the natural rate of interest while the inflation target has been close to 2% over the last decade.     

Exploring PMOs through community of practice theory

This article explores project management offices (PMOs) through community of practice theory. Preliminary results from a national health care case study are used to confirm the legitimacy of this approach. Today's knowledge‐based economy calls for mechanisms to share knowledge. The issue of making more with less is at stake in order to reuse good practices, support innovative practice, and prevent the reinvention of the wheel. Members of these communities are at the heart of the learning process. The originality of this research is that it sheds light on PMOs in a new theoretical perspective within the field of knowledge management.     

Ökonomische Folgen eines Atomausstiegs in Deutschland

Nach der Atomkatastrophe in Fukushima hat die Bundesregierung beschlossen, bis Mitte Juni die Zukunft der Atomenergie in Deutschland zu überdenken. Dabei k?nnen unterschiedlich weitgehende Szenarien betrachtet werden. Sie reichen von einer Rücknahme der im letzten Herbst beschlossenen Laufzeitverl?ngerung bis hin zum vollkommenen Ausstieg aus der Kernkraft. Die Autoren vertreten grunds?tzlich die Auffassung, dass die wirtschaftlichen Folgen eines Atomausstiegs zu bew?ltigen sind. Mit einer Steigerung der Energiepreise muss allerdings gerechnet werden — wie deutlich diese ausf?llt, und welche Referenzwerte herangezogen werden müssen, h?ngt von vielen Faktoren ab.