Unequal probability sampling in fixed area plots of stem volume with and without prior inclusion probabilities

The impact of guessing auxiliary population attributes, as opposed to relying on actual values from a prior survey, was quantified for three unequal probability sampling methods of tree stem volume (biomass). Reasonable prior guesses (no-list sampling) yielded, in five populations and 35 combinations of population size and sample size, results at par with sampling with known auxiliary predictors (list sampling). Realized sample sizes were slightly inflated in no-list sampling with probability proportional to predictions ( PPP ). Mean absolute differences from true totals and root mean square errors in no-list-sampling schemes were only slightly above those achieved with list sampling. Stratified sampling generally outperformed PPP and systematic sampling, yet the latter is recommended due to consistency between observed and expected mean square errors and overall robustness against a systematic bias in no-list settings.     

Ownership concentration and market value of European banks

This paper investigates the relationship between ownership concentration and market value of European banks, and the role of the institutional environment in shaping this relationship. Using GMM dynamic estimator on a sample of European banks over a 13-year period (1993–2005) we find on average a negative effect of ownership concentration on bank value, measured by Tobin's Q. However, this effect varies across different institutional settings; while higher ownership concentration results in a lower bank value particularly in the countries belonging to German legal family, the impact of ownership concentration is positive in Scandinavia. We propose that, besides the legal protection of small investors, the differences in the impact of ownership concentration across the countries could be due to the identity of the predominant owners, i.e. financial institutions in Germany and trusts and foundations in Scandinavia. This in turn implies that restrictions of shareholdings in banks could alleviate governance problems in some countries, but lower bank valuation in others.     

Event frequency,excitement and desire to gamble,among pathological gamblers

In this study we compared gambling behaviour of 15 pathological gamblers (PG) and 15 non-problem gamblers (NPG) on two conditions of a commercially available slot machine. One condition used a commercially available two-second event frequency (games per minute), while the other condition used an experimental three-second event frequency. The payback percentage (wins relative to losses) and reward frequency (wins over number of games played) varied randomly across conditions. The results showed that PG had significantly higher measures than NPG on time spent gambling, excitement level and desire to play again in the two-second condition. In the three-second condition there were no differences in excitement level and desire to play again. The number of PG playing the maximum time (60 minutes) was reduced in the three-second version, and reward frequency contributed to reduction in time spent gambling. The results may have implications for understanding behavioural mechanisms of pathological gambling among slot machine players.     

Quantification of symmetry for functional data with application to equine lameness classification

This paper presents a study on symmetry of repeated bi-phased data signals, in particular, on quantification of the deviation between the two parts of the signal. Three symmetry scores are defined using functional data techniques such as smoothing and registration. One score is related to the L ₂-distance between the two parts of the signal, whereas the other two are constructed to specifically measure differences in amplitude and phase. Moreover, symmetry scores based on functional principal component analysis (PCA) are examined. The scores are applied to acceleration signals from a study on equine gait. The scores turn out to be highly associated with lameness, and their applicability for lameness quantification and detection is investigated. Four classification approaches turn out to give similar results. The scores describing amplitude and phase variation turn out to outperform the PCA scores when it comes to the classification of lameness.     

The effects of vocational training programmes on the duration of unemployment in Eastern Germany

Summary Vocational training programmes have been the most important active labour market policy instrument in Germany in the last years. However, the still unsatisfying situation of the labour market has raised doubt on the efficiency of these programmes. In this paper, we analyse the effects of the participation in vocational training programmes on the duration of unemployment in Eastern Germany. Based on administrative data for the time between the October 1999 and December 2002 of the Federal Employment Administration¹, we apply a bivariate mixed proportional hazards model. By doing so, we are able to use the information of the timing of treatment as well as observable and unobservable influences to identify the treatment effects. The results show that a participation in vocational training prolongates the unemployment duration in Eastern Germany. Furthermore, the results suggest that locking-in effects are a serious problem of vocational training programmes. The authors thank Heinz Galler and an anonymous referee for valuable comments. The paper has also benefited from fruitful discussion at the annual meeting of the German Statistical Society in 2004, Frankfurt, and in IZA seminar, Bonn. All remaining errors are on our own. Financial support of the IAB, Nuremberg, is gratefully acknowledged.     

An equivalence test for comparing DNA sequences

The practice of sequence alignment is constantly oscillating between the risk of overlooking important structure and that of discovering any arbitrarily defined kind of structure anywhere. On the other hand, the use of a condensed consensus sequence may lead to a substantial loss in valuable information. While adopting a Mahalanobis‐type index we allow for a certain degree of uncertainty in the measurements. This uncertainty may be caused by inaccurate measurements or ambiguity. In this paper, we test the similarity between DNA sequences within the framework of equivalence testing, accounting for both variances and covariances between frequencies of nucleotides. Statistical methods for testing equivalence were first developed in the context of pharmacokinetics and later extended to the field of clinical trials. Nowadays, (bio)equivalence tests seem to be less frequently used outside the drug testing field, including statistical genetics. Copyright © 2005 John Wiley & Sons, Ltd.     

The labor force implications of expanding the child care industry

This paper examines the labor force implications of increased social investment in the child care industry. We have two main conclusions to report. First, expanding the child care industry will remove a major barrier to employment for a sizable number of women. This includes women in middle and upper income families who desire to work for personal fulfillment and to improve their families' lifestyles. But even more so, it includes women in low-income and single-parent families who need to work to maintain a minimal and dignified standard of living and who might otherwise remain dependent on welfare benefits for their own and their families' subsistence. Second, expanding the child care industry will help employers cope with a range of personnel problems they will increasingly face as the U.S. undergoes a major transition in the 1990's from being a labor surplus economy to being a labor shortage economy.