Analysis of exacerbation rates in asthma and chronic obstructive pulmonary disease: example from the TRISTAN study

Recurrent events in clinical trials have typically been analysed using either a multiple time-to-event method or a direct approach based on the distribution of the number of events. An area of application for these methods is exacerbation data from respiratory clinical trials. The different approaches to the analysis and the issues involved are illustrated for a large trial (n = 1465) in chronic obstructive pulmonary disease (COPD). For exacerbation rates, clinical interest centres on a direct comparison of rates for each treatment which favours the distribution-based analysis, rather than a time-to-event approach. Poisson regression has often been employed and has recently been recommended as the appropriate method of analysis for COPD exacerbations but the key assumptions often appear unreasonable for this analysis. By contrast use of a negative binomial model which corresponds to assuming a separate Poisson parameter for each subject offers a more appealing approach. Non-parametric methods avoid some of the assumptions required by these models, but do not provide appropriate estimates of treatment effects because of the discrete and bounded nature of the data.     

Analyzing Precautionary Regulation: Do Precaution,Science, and Innovation Go Together?

In this article we argue that the precautionary principle, as applied to the regulation of science and technology, cannot be considered in any general manner inconsistent with the norms and methods of scientific knowledge generation and justification. Moreover, it does not necessarily curtail scientific‐technological innovation. Our argument flows from a differentiated view of what precaution in regulation means. We first characterize several of the most relevant interpretations given to the precautionary principle in academic debate and regulatory practice. We then use examples of actual precaution‐based regulation to show that, even though science can have varying functions in different circumstances and frames, all of those interpretations recur to scientific method and knowledge, and tend to imply innovation in methods, products, and processes. In fact, the interplay of regulation and innovation in precautionary policy, at least in the case of the interpretations of precaution that our analysis takes into account, could be understood as a way of reconciling the two fundamental science and technology policy functions of promotion and control.     

Are crowds on the internet wiser than experts? The case of a stock prediction community

According to the “Wisdom of Crowds” phenomenon, a large crowd can perform better than smaller groups or few individuals. This article investigates the performance of share recommendations, which have been published by members of a stock prediction community on the Internet. Participants of these online communities publish buy and sell recommendations for shares and try to predict the stock market development. We collected unique field data on 10,146 recommendations that were made between May 2007 and August 2011 on one of the largest European stock prediction communities. Our results reveal that on an annual basis investments based on the recommendations of Internet, users achieve a return that is on average 0.59 % points higher than investments of professional analysts from banks, brokers and research companies. This means, that on average, investors are better off by trusting the crowd rather than analysts. We furthermore investigate how the postulated theoretical conditions of diversity and independence influence the performance of a large crowd on the Internet. While independent decisions can substantially improve the performance of the crowd, there is no evidence for the power of diversity in our data.     

HOW DO INFORMAL AGREEMENTS AND REVISION SHAPE CONTRACTUAL REFERENCE POINTS?

The notion of contracts as reference points provides the basis for a deeper understanding of important phenomena such as the employment contract, vertical integration, firm scope, authority, and delegation. Previous experiments lend support to this notion but they ignore realistic aspects of trading relationships such as informal agreements and ex‐post renegotiation or revision. Here we show that the central behavioral mechanism underlying contractual reference points is robust to such considerations. Our data reveal that informal agreements can mitigate the trade‐off between rigidity and flexibility but they do not fully resolve the problem of misaligned reference points. Our experiments also show that contract revision is a more nuanced process than the previous literature has recognized. We find, for example, that it is sometimes better for parties to write a simple (rigid) contract and then revise it ex post if needed, rather than to anticipate and include future contingencies in a (flexible) contract from the outset.     

Profitieren Kinder mit Migrationshintergrund von pädagogischen Fachkräften mit Migrationshintergrund?Do migrant children benefit from migrant teachers?

This paper tests the assumption that a stronger presence of migrant teachers in preschool can help to reduce ethnic disadvantages and contribute to more equality of opportunity. To this end, migrant children who are taught by teachers with a migration background are compared to those who are confronted with only autochthonous teachers in their day-care centre. The outcome variables include competencies in German language, mathematics, science, as well as social competencies of the children. In addition, the study investigates the contact frequency of migrant parents with the day care centre to test whether contact is enhanced in centres which employ migrant teachers. Contrary to expectations, propensity score matching analyses based on the Kindergarten cohort of the German National Educational Panel Study (NEPS) show that migrant children do not achieve higher competencies when being taught by migrant teachers. Similarly, contact to migrant parents is not improved. More teachers with a migration background will hardly reduce ethnic disadvantages in educational outcomes.     

Understanding Contemporary Challenges to INGO Legitimacy: Integrating Top-Down and Bottom-Up Perspectives

In recent years, INGO legitimacy has been subject to growing scrutiny from analysts and practitioners alike. Critics have highlighted a backlash against INGOs in the Global South, a growing mismatch between INGO capacities and contemporary global challenges, and diminishing support for norms such as democracy and human rights that underpin INGOs’ work. Although these problems have attracted significant attention within the academic literature, this article argues that existing explorations of INGO legitimacy have broadly conformed either to a top-down approach focused on global norms and institutions or a bottom-up approach focused on the local dynamics surrounding states and populations in the Global South. We suggest that this divide is unhelpful for understanding the current predicament and propose a new approach, which pays closer attention to the interaction between bottom-up and top-down dimensions, and to historical context. This new approach can provide important insights into current debates about the future roles and internal structures of INGOs.     

Rewriting history: the case of the Disability Discrimination Act 1995

The Disability Discrimination Act was 20 years old in 2015 and received much attention, being presented as a cause for celebration. In what follows I suggest that this is far from being an accurate assessment of its impact and go on to suggest that it was not achieved as a result of a broad consensus but rather the product and ultimate betrayal of the hopes and dreams of disabled people ourselves. As such, my version of this history has important lessons for disabled people ourselves.     

Adaptive testing in arch models

Specification tests for conditional heteroskedasticity that are derived under the assumption that the density of the innovation is Gaussian may not be powerful in light of the recent empirical results that the density is not Gaussian. We obtain specification tests for conditional heteroskedasticity under the assumption that the innovation density is a member of a general family of densities. Our test statistics maximize asymptotic local power and weighted average power criteria for the general family of densities. We establish both first-order and second-order theory for our procedures. Simulations indicate that asymptotic power gains are achievable in finite samples.     

Net migration and migration effectiveness: A comparison between Australia and the United Kingdom, 1976–96 Part 1: Total migration patterns

A nation’s population is redistributed through migration flows and counterflows between its constituent subnational areas, resulting in a geographical pattern of net migration gains or losses which may change from one time period to another. Migration effectiveness is the indicator commonly used to measure net migration as a proportion of gross migration turnover for any territorial unit. This paper explores the effect of net migration in two different countries, Australia and the United Kingdom, using measures of migration effectiveness computed from period-age migration data sets for a system of city regions assembled for four consecutive five-year periods in each country. While the evidence suggests that the overall effectiveness of net migration has declined over the 20-year period in both countries, marked similarities and contrasts are apparent in the spatial patterning of migration that together provide useful analytical insights into the changing space economies of the two countries.     

Transition into Retirement Affects Life Satisfaction: Short- and Long-Term Development Depends on Last Labor Market Status and Education

The effect of retirement on life satisfaction is a research topic that received a lot of attention, yet provided heterogeneous results. The current study suggests a remedy for this situation by taking two predictors of diversity (i.e. education and last labor market status) into account. We assumed that changes in social status and changes in resources influence retirement adjustment. The social status change affects retirees in the short-term, whereas individuals’ resources indicated by education predict long-term adjustment. To disentangle these processes, we contrasted exits from full-time employment and transitions from unemployment. We used data from the German Socio-Economic Panel to estimate a multi-group, multi-episodes dual change score model. The development of life satisfaction is lastingly interrupted by retirement. A short-term increase in life satisfaction was found for both transition groups but was more pronounced for those being previously unemployed. Life satisfaction develops in the long-term education-specific: retirees who have more education show almost constant life satisfaction whereas those retirees who have less education experience a decline. The results indicate that retirement entails a major change in the way people live. Adjustment to this can be characterized by two processes: A status change enfolds in the short-term. A building of new daily routines using individuals’ resources develops in the long-term. Both processes can be interpreted in terms of cumulative inequality: last labor market status differences decrease in the short-term but remain. Educational differences increase after retirement.