Testing for Structural Breaks at Unknown Time: A Steeplechase
Makram El-Shagi, Sebastian Giesen
Abstract
This paper analyzes the role of common data problems when identifying structural breaks in small samples. Most notably, we survey small sample properties of the most commonly applied endogenous break tests developed by Brown, Durbin, and Evans (1975) and Zeileis (2004), Nyblom (1989) and Hansen (1992), and Andrews, Lee, and Ploberger (1996). Power and size properties are derived using Monte Carlo simulations. Results emphasize that mostly the CUSUM type tests are affected by the presence of heteroscedasticity, whereas the individual parameter Nyblom test and AvgLM test are proved to be highly robust. However, each test is significantly affected by leptokurtosis. Contrarily to other tests, where skewness is far more problematic than kurtosis, it has no additional effect for any of the endogenous break tests we analyze. Concerning overall robustness the Nyblom test performs best, while being almost on par to more recently developed tests in terms of power.
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Shrinking due to corpulence? BMI in childhood predicts subsequent linear growth among US children and youth, 1963-1970
Marco Sunder
Annals of Human Biology,
2008
Abstract
While the USA is one of the most opulent countries, its population is not among the tallest but is among the most corpulent. This short report investigates the association between body mass index in childhood and subsequent change in height-for-age at the individual level, based on data from the National Health Examination Study (1963-1970). A sub-sample of participants in this survey was measured twice at intervals between 2.3 and 4.4 years, and assessed bone age can be used to account for differences in maturation at baseline. Regression results indicate that a BMI-for-age above the 85th percentile is associated with a reduction in growth by 0.03-0.06 height-for-age standard deviations per year, or roughly 1 cm within 4 years. An inefficiently high nutritional status in childhood may thus jeopardize subsequent linear growth. However, the trans-Atlantic height gap is considerably larger than what this empirical relationship could predict.
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Comparing the training activities of unemployed and full-time employed people
Birgit Schultz, Joachim Wilde
Zeitschrift für Arbeitsmarktforschung,
No. 1,
2008
Abstract
Many empirical studies for Germany consider either the training activities of the unemployed or those of employees. However, a comprehensive comparison of both groups had not been conducted until now. The paper closes this gap. Using data from the latest time-use survey (Zeitbudgeterhebung) of the Federal Statistical Office, the amount of training undertaken by the two groups is compared. Furthermore, the types of activities that are made use of in particular are described. Heterogeneity due to different relevant socioeconomic characteristics in the two groups is eliminated by applying a matching procedure. The findings demonstrate that only 49% of unemployed people participate in any kind of training activity off the job. In the case of full-time employment 59 % would take part. Concerning the average expenditure of time per week the difference is reversed, i.e. the expenditure of time is greater during unemployment. However, a large proportion of the training activities undertaken by the unemployed comprises general training, e.g. by reading books or watching television. Furthermore, the result is driven by a different potential of time that can be used for training activities off the job. In relation to this potential of time, the amount of training activity is still smaller during unemployment.
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Technologie- und Gründerzentren im Lichte von Diversifizierung versus Spezialisierung
Michael Schwartz, Christoph Hornych
IWH Discussion Papers,
No. 7,
2008
Abstract
In Germany, a growing tendency can be observed to focus business incubators (BIs) and technology centers and their respective support elements and processes as well as the selection criteria applied by the incubator management on firms from solely one sector or few but complementary sectors and their specific needs and requirements. These are called specialized business incubators (SBIs). Despite the increasing importance of specialization strategies of business incubators as local and regional policy instruments, there are no reliable empirical examinations of the specifics, and advantages in particular, of SBIs compared to more diversified BIs. On the basis of survey-data, that comprises responses from 161 actual firms incubated in 13 diversified BIs and 13 specialized BIs in Germany, this study investigates the mechanisms within the specific context of specialized BIs and their value-added contribution versus the more diversified incubation model. For the first time, this study provides large-scale empirical evidence concerning the effects of adopting a specialization strategy in the context of business incubation.
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Foreign Subsidiaries in the East German Innovation System – Evidence from Manufacturing Industries
Jutta Günther, Björn Jindra, Johannes Stephan
IWH Discussion Papers,
No. 4,
2008
Abstract
This paper analyses the extent of technological capability of foreign subsidiaries located in East Germany, and looks at the determinants of foreign subsidiaries’ technological sourcing behaviour. The theory of international production underlines the importance of strategic and regional level variables. However, existing empirical approaches omit by and large regional level factors. We employ survey evidence from the “FDI micro data- base” of the IWH, that was only recently made available, to conduct our analyses. We find that foreign subsidiaries are above average technologically active in comparison to the whole East German manufacturing. This can be partially explained by the industrial structure of foreign direct investment. However, only a limited share of foreign subsidiaries with R&D and/or innovation activity source technological knowledge from the East German innovation system. If a subsidiary follows a competence augmenting strategy or does local trade, it is more likely to source technological knowledge locally. The endowment of a region with human capital and a scientific infrastructure has a positive effect too. The findings suggest that foreign subsidiaries in East Germany are only partially linked with the regional innovation system. Policy implications are discussed.
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East German Innovation System attractive for Foreign Investors
Jutta Günther, Björn Jindra, Johannes Stephan
Wirtschaft im Wandel,
No. 1,
2008
Abstract
Foreign direct investment (FDI) plays an important role in the catching-up process of East Germany due to direct employment- and demand related effects. However, this article takes a technological perspective on FDI in East Germany. It considers technological activities of foreign investors (R&D and innovation) and asks to what extent these are integrated into the East German innovation system. In other words, do foreign investors interact technologically with domestic enterprises and scientific institutions? So far, there seems to be a striking absence of empirical evidence on this issue. The basis for our analysis is recent data from a representative survey of foreign direct investors in East German manufacturing completed in 2007. The findings show that on average foreign investors are more R&D and innovation intensive compared to the total of East German manufacturing. In addition, their technological activities are by no means isolated from the East German innovation system. Foreign subsidiaries seem to benefit from East German customers, suppliers and especially scientific institutions with regard to locally conducted R&D and innovation. Contrary to existing assumptions the East German innovation system seems to be particularly attractive for the most technologically active foreign subsidiaries. This could constitute a major locational advantage for FDI in East Germany over Central and East Europe. However, the technologically active foreign investors believe that only East German suppliers are able to benefit from their technological cooperation. The same cannot be said about East German customers or competitors. Thus, the potential for technological externalities from FDI in East Germany seems still to be limited.
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Vergleich der Weiterbildungsaktivitäten von Arbeitslosen und Vollzeiterwerbstätigen
Birgit Schultz, Joachim Wilde
IWH Discussion Papers,
No. 9,
2007
Abstract
Many empirical studies consider either training activities of the unemployed or training activities of the employees in Germany. However, a comprehensive comparison of both groups is missing. The paper closes this gap. Using data of the latest time use survey (Zeitbudgeterhebung) of the Federal Statistical Office, the amount of training is compared for both groups. Furthermore, it is described which types of activities are made use of in particular. Heterogeneity due to different relevant socioeconomic characteristics in the two groups is eliminated by the appliance of a matching procedure. Findings demonstrate that only 49% of the unemployed persons participate in any kind of training activities off the job. In case of the full-time employment 59 % would take part. Concerning the average expenditure of time per week the difference turns around, i.e. the expenditure of time is higher during unemployment. However, a high proportion of the training activities of the unemployed falls upon general training, e.g. by reading books or watching TV. Furthermore, the result is driven by a different potential of time that can be used for training activities off the job. Relating to this potential of time the amount of training activities is still lower during unemployment.
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Zeitpotential für berufliche Weiterbildung von Arbeitslosen wenig genutzt
Joachim Wilde, Birgit Schultz
Wirtschaft im Wandel,
No. 5,
2007
Abstract
In general, unemployed persons spend more time on further training than full-time employees. Using data of the latest time use survey (Zeitbudgeterhebung) of the Federal Statistical Office, this study analyzes whether this higher potential of time is being used or not. Furthermore, it describes which types of activities are made use of in particular. Heterogeneity due to different relevant socioeconomic characteristics in the two groups is eliminated by the appliance of a matching procedure.
Findings demonstrate that only around 15 % of the unemployed persons participate in further training activities off the job. In case of the full-time employment just under 40 % of the persons would take part. Relating to the average expenditure of time per week the difference decrease clearly. However, altogether the expenditure of time is not higher during unemployment.
A selection of subsamples points out different results, i.e. in some subsamples the expenditure of time for further training is larger during unemployment. However, in the subsample of low skilled persons these results are mainly caused by activities like hearing radio or watching TV. Thus, it is doubtful whether the higher expenditure of time qualifies for the primary labour market.
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Microeconometric Evaluation and the Selection Bias – A practical Survey of Nonparametrical Solution Methods
Eva Reinowski
Zeitschrift für Evaluation 2,
No. 2,
2006
Abstract
The application of evaluation strategies becomes more important in various fields of study. The problem of self-selection associated with microeconomic evaluation can be solved in different ways, but nonparametrical solutions are most popular. The study gives an overview of nonparametrical solution methods for this problem. The aim is to close the gap between introductory and the more sophisticated literature and to give some practical guidance for the choice of the appropriate method for empirical application. The assumptions as well as advantages and drawbacks for empirical application and the requirements to the data base are described for every approach. It becomes clear that there is no ‘magic bullet’. For an unbiased estimation the assumptions have to be fulfilled and the data at hand must be compatible with the respective method.
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Entry and Strategic Information Display in Credit Markets
Jan Bouckaert, Hans Degryse
Economic Journal,
No. 513,
2006
Abstract
In many countries, lenders voluntarily provide information about their borrowers to private credit registries. A recent World Bank survey reveals that the display of a lender's own borrower information is often not reciprocated. That is, access to these registries does not require the prior provision of proprietary data. We argue that incumbent lenders release information about a portion of their profitable borrowers for strategic reasons. The reasoning is that the pool of unreleased borrowers becomes characterised by a severe adverse selection problem. This prevents the entrants from bidding for all the incumbent's profitable borrowers and reduces their scale of entry.
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