Entropy of unequal probability sampling designs

There exist many designs for unequal probability sampling. In this paper entropy, which is a measure of randomness, is used to compare eight designs. Both old and commonly used designs and more recent designs are included. Several different and general estimates of entropy are presented. In the quest of finding entropy, expressions for the probability function are derived for different designs. One of them is a recent general design called correlated Poisson sampling. Several designs are close to having maximum entropy, which means that the designs are robust. A few designs yield low entropy and should therefore in general be avoided.     

Dynamic Pricing in the Presence of Myopic and Strategic Consumers: Theory and Experiment

We investigate retailers’ dynamic pricing decisions in a stylized two‐period setting with possible supply constraints and demand from both myopic and strategic consumers. We present an analytical model and then test its predictions in a behavioral experiment in which human subjects played the role of pricing managers. We find that the fraction of strategic consumers in the market systematically moderates the optimal pricing structure. When this fraction exceeds a certain threshold, the retailer offers relatively small late season markdowns to discourage strategic consumers from waiting and to incentivize them to buy during the early season; otherwise, the retailer offers relatively large markdowns to divert all strategic consumers to the late season, where the majority of revenue is made. Our model analyses suggest that the latter policy is optimal under fairly broad conditions. Our experiment shows that after some significant learning, aggregate behavior is able to approximate the key qualitative predictions from our model analysis, with one notable deviation: in the presence of a mixture of myopic and strategic consumers, subjects act somewhat myopically – they underprice and oversell in the main selling season, which significantly limits their ability to generate revenue in the markdown season.     

Overcoming barriers: Effects of entering vocational rehabilitation on labour market outcomes

Vocational rehabilitation aims at getting people with health problems or disabilities back into work. In Germany, the Public Employment Service is a central provider of vocational rehabilitation services targeted at unemployed people. Against this background, the study examined the labour market effects of vocational rehabilitation for people registered as unemployed with the Public Employment Service. A comparison of the accepted and the rejected applicants for vocational rehabilitation using inverse probability weighting based on propensity scores provides an insight into its effects. The results suggest that the employment prospects of persons who were accepted in the programme improved modestly after the third‐year following application. A subgroup analysis identified stronger re‐employment effects of acceptance into vocational rehabilitation in eastern Germany as well as for men and older individuals.     

Case-based methods and agent-based modelling: bridging the divide to leverage their combined strengths

Two leading camps for studying social complexity are case-based methods (CBM) and agent-based modelling (ABM). Despite the potential epistemological links between ‘cases’ and ‘agents,’ neither camp has leveraged their combined strengths. A bridge can be built, however, by drawing on Abbott’s insight that ‘agents are cases doing things’, Byrne’s suggestion that ‘cases are complex systems with agency’, and by viewing CBM and ABM within the broader trend towards computational modelling of cases. To demonstrate the utility of this bridge, we describe how CBM can utilise ABM to identify case-based trends; explore the interactions and collective behaviour of cases; and study different scenarios. We also describe how ABM can utilise CBM to identify agent types; construct agent behaviour rules; and link these to outcomes to calibrate and validate model results. To further demonstrate the bridge, we review a public health study that made initial steps in combining CBM and ABM.     

The choice among past trends as a basis for the prediction of future trends in old-age mortality

We explored the extent to which projections of future old-age mortality trends differ when different projection bases are used. For seven European countries, four alternative sets of annual rates of mortality change were estimated with age-period log-linear regression models, and subsequently applied to age-specific all-cause mortality rates (80+) in 1999 to predict mortality levels up to 2050. On average, up to 2050, e80 is predicted to increase further by 2.33 years among men and 4.03 years among women. Choosing a historical period of 25 instead of 50 years results in higher predicted gains in e80 for men but lower gains for women. Choosing non-smoking-related mortality instead of all-cause mortality leads to higher gains for women and mixed results for men. In all alternatives there is a strong divergence of predicted mortality levels between the countries. Future projections should be preceded by a thorough study of past trends and their determinants.     

Spatial configurations of urban forest in different landscape and socio-political contexts: identifying patterns for green infrastructure planning

Rapid urbanisation and climate change have motivated the development of urban green infrastructure (UGI) as a planning strategy to support the wellbeing of urban people and ecosystems while parallel adapting cities to climate change. Forest (tree-covered areas >0.5 ha) is a key UGI component that afford a wider range of ecosystem services and mitigate urban heat islands more effectively than non-wooded green spaces. However, understanding of spatial configurations (variation in patch size and frequency) of forests across the gradient of urbanisation and between cities is limited to case studies. This represents a considerable knowledge gap for identification of general patterns that can inform integration of forest resources in UGI planning that have value beyond the individual city level. In this study we used Geographic Information Systems to explore the spatial configuration of forests across cities located within landscapes characterised by different levels of anthropogenic modification (degree of forest cover) and socio-political contexts, i.e. all Danish and Swedish cities >10,000 inhabitants (n = 176). We applied general linear modelling to investigate the relationship between forest cover, patch size and frequency with 1) regional landscape type, 2) demographic trends 1960–2010, and 3) the gradient of urbanisation (measured in three zones: urban core (0.2 km from city boundary), urban fringe (0.2–2 km), and urban periphery (2–5 km)). Regardless of demographic trends, forest cover was lowest in cities settled in large-scale agricultural regions, higher in regions with mosaics of forest and farming, and highest in forest-dominated regions. However, in all cities forest cover was lowest in the urban zone and peaked on the urban fringe rather than on the urban periphery. Furthermore, pocket woods (0.5–2 ha) accounted for over 50 % of patches in all three urban zones, irrespective of regional landscape type. We conclude by discussing how these general patterns could inform strategies for integration of urban forests in UGI planning.     

Modelling free social spaces and the diffusion of social mobilization

Free social spaces have long been emphasized in the social movement literature. Under names such as safe spaces, social havens, and counterpublics, they have been characterized as protective shelters against prevailing hegemonic ideologies and as hubs for the diffusion of ideas and ideologies. However, the vast literature on these spaces has predominantly focused on internal dynamics and processes, thus neglecting how they relate to the diffusion of collective mobilization. Inspired by formal modeling in collective action research, we develop a network model to investigate how the structural properties of free social spaces impact the diffusion of collective mobilization. Our results show that the assumption of clustering is enough for structural effects to emerge, and that clustering furthermore interacts synergistically with political deviance. This indicates that it is not only internal dynamics that play a role in the relevance of free social spaces for collective action. Our approach also illustrates how formal modeling can deepen our understanding of diffusion processes in collective mobilizations through analysis of emergent structural effects.     

What is new with old? What old age teaches us about inequality and stratification

Aging is remarkably unequal. Who survives to grow old in America and the circumstances they face once there reflect durable racial, socioeconomic, and gender inequalities that structure our lives from birth. Yet within the field of social stratification and mainstream sociology proper, examinations of the rapidly growing population of older Americans are often relegated to a “gerontological” periphery. This essay posits that the failure to place aging as a core concern in stratification and inequality is a missed opportunity. We argue for the importance of reintegrating studies on the stratification of aging and explain why such a move is necessary. Specifically, we posit that (a) examining the aging population is necessary for understanding American inequality because aging is an outcome that is ubiquitous yet highly stratified; (b) aging and being seen as “old” in a youth‐focused society are stratifying processes in their own right; and (c) later life provides for analytical comparisons that are illustrative of how key mechanisms of inequality structure and stratify. After examining insights provided by a new wave of research on the aging U.S. population, we revisit the implications for understanding inequality and stratification in a graying and unequal America.     

An Analysis of Independent Power Projects in Africa: Understanding Development and Investment Outcomes

This study analyses the outcomes of African independent power projects (IPPs). Nearly 40 such projects have taken root to date, concentrated mainly in 8 countries. More balanced outcomes are perceived in North Africa than across sub‐Saharan Africa (SSA), for reasons linked to more attractive investment environments, more robust policy frameworks, fewer planning mishaps, abundant low‐cost fuel and secure fuel contracts as well as credit enhancements such as sovereign guarantees. With few exceptions, these elements were absent in SSA, where the role of development finance institutions and the strategic management of projects seem more important.     

A Cognitive Career Course: From Theory to Practice

A university career development course based on cognitive information‐processing theory was assessed. Students who took the course showed a significant decrease in their negative career thoughts when the Career Thoughts Inventory (J. P. Sampson, G. W. Peterson, J. G. Lenz, R. C. Reardon, & D. E. Saunders, 1996a) was used as a pretest and posttest measure. The greatest decrease in negative thinking was found in students with the highest level of negative thinking at the beginning of the course. The specific components of negative career thinking—decision‐making confusion and commitment anxiety—contributed significantly to the main effect. There were no significant interactions with ethnicity or sex.