Improved inference for MCP-Mod approach using time-to-event endpoints with small sample sizes

The Multiple Comparison Procedures with Modeling Techniques (MCP-Mod) framework has been recently approved by the U.S. Food, Administration, and European Medicines Agency as fit-for-purpose for phase II studies. Nonetheless, this approach relies on the asymptotic properties of Maximum Likelihood (ML) estimators, which might not be reasonable for small sample sizes. In this paper, we derived improved ML estimators and correction for their covariance matrices in the censored Weibull regression model based on the corrective and preventive approaches. We performed two simulation studies to evaluate ML and improved ML estimators with their covariance matrices in (i) a regression framework (ii) the Multiple Comparison Procedures with Modeling Techniques framework. We have shown that improved ML estimators are less biased than ML estimators yielding Wald-type statistics that controls type I error without loss of power in both frameworks. Therefore, we recommend the use of improved ML estimators in the MCP-Mod approach to control type I error at nominal value for sample sizes ranging from 5 to 25 subjects per dose.     

A note on the optimal level of public inputs

This paper analyses whether the first-best level of public inputs exceeds the second-best level. On the basis of a simple model, we argue that the level of productivity-enhancing public expenditures is always higher than the level of public inputs provided with distortionary taxation.     

Are invasive House Sparrows a nuisance for native avifauna when scarce?

Biological invasions are the second most important cause of species extinction. Aided by processes such as transportation and urbanization, exotic species can establish and spread to new locations, causing changes in the function and structure of ecosystems. The House Sparrow is a widespread and highly abundant landbird associated to human presence. Previous studies performed in urban landscapes have suggested that this species could be acting, in synergy with urbanization, as a potential threat to native urban avian assemblages. In this study we assessed the relationship between House Sparrow density and native bird species richness in a region where the sparrows are scarce and sparsely distributed. We surveyed bird assemblages in and around four small-sized human settlements, considering three conditions in relation to House Sparrow presence: urban invaded, urban non-invaded, and non-urban non-invaded. To assess the potential detrimental role of House Sparrows on native bird species richness, we measured, additionally to sparrow densities, 20 predictor variables that describe vegetation structure and complexity, as well as urban infrastructure and human activities across four seasons of 1 year. Our results show that maximum shrub height was positively related to bird species richness, built cover was negatively associated with it, and House Sparrow invaded sites were related to a significant decrease of bird species richness, with increasing richness loss when more sparrows were present. Thus, we here provide evidence that urban areas can act in synergy with the presence of House Sparrows (even in low densities) in the urban-related species richness decline pattern.

     

Opportunities and challenges of the digital lifespan: views of service providers and citizens in the UK

Information about UK citizens’ use of digital technologies is often expressed in statistics – x% lack Internet access; y% get online to engage in online banking, update social media sites, or participate in online auctions. There are many social implications to digital technology use, however – individuals may communicate online as a major way to stay in touch with friends and family, and as Internet access rises and government and public sector budgets shrink, online services become an increasingly attractive way for government and public sector service providers to communicate with citizens. This paper presents selected results of an exploratory study designed to investigate the digital personhood of UK citizens through interviews with participants at three life transitions: leaving secondary school, becoming a parent, and retiring from work. Digital personhood in this paper implies identity information online, and some interaction with others around that information. We then report on our presentation of a selection of these results to thirteen stakeholders who represented UK government departments, public sector organisations, and industry. We found that citizen and stakeholder concerns were quite different, especially at the new parent life transition, and that stakeholders tended to underestimate the willingness and ability of citizens to become involved online with the government and public sector, and overestimate citizens’ vulnerability online. Future research should investigate practical strategies for increasing communication between stakeholders and citizens, and also how to encourage stakeholders to work together to benefit their common clientele – the citizens.     

Measures of Social Isolation

Social isolation is a deprivation of social connectedness. It is a crucial aspect that continues to be named by people as a core impediment for achieving well-being and as a relevant factor for understanding poverty. However it is not routinely included in surveys that provide data on multidimensional poverty measurement. Although the challenge of measuring social connectedness is daunting, this paper argues that existing research in several fields provides solid ground for the construction of basic internationally comparable indicators that measure specific aspects of social isolation. In particular, this paper synthesises the relevant literature on the measurement of social isolation and related phenomena, and on the basis of this synthetic review, proposes a module of indicators to measure social connectedness that could be feasibly incorporated into an internationally comparable multi-topic household survey.     

Exploring the Complex Associations Among Social Determinants of Health in Andalusia After the 2008 Financial Crisis

Social Indicators Research - In this study, we disentangle the complex relationship between structural and intermediary social determinants of health in Andalusia (Spain) after the period of...     

The Relational Antecedents of Interpersonal Helping: ‘Quantity’, ‘Quality’ or Both?

Having a large network of colleagues means having several opportunities to help those colleagues, as well as a higher chance of receiving requests for help from them. Employees with large networks are therefore expected to help more in the workplace than those with small networks. However, large networks are also associated with cognitive costs, which may reduce the focal employee's ability to both recognize the need for help and engage in helping behaviours. For these reasons, the authors assert an inverted U‐shaped relation between the size of an ego's social network and engagement in helping behaviour. However, high‐quality relationships imply higher mutual understanding between the actors, and hence lower cognitive costs. In turn, the position (and threshold) of the curve between network size and interpersonal helping should be influenced by the quality of the relationship between the provider and the beneficiaries of help. Analysis of employee‐level, single‐firm data supports these ideas, providing preliminary evidence that quality of relationship compensates for the difficulties that may arise from having large social networks.