Identifying treatment effects using trimmed means when data are missing not at random

Patients often discontinue from a clinical trial because their health condition is not improving or they cannot tolerate the assigned treatment. Consequently, the observed clinical outcomes in the trial are likely better on average than if every patient had completed the trial. If these differences between trial completers and non-completers cannot be explained by the observed data, then the study outcomes are missing not at random (MNAR). One way to overcome this problem—the trimmed means approach for missing data due to study discontinuation—sets missing values as the worst observed outcome and then trims away a fraction of the distribution from each treatment arm before calculating differences in treatment efficacy (Permutt T, Li F. Trimmed means for symptom trials with dropouts. Pharm Stat. 2017;16(1):20–28). In this paper, we derive sufficient and necessary conditions for when this approach can identify the average population treatment effect. Simulation studies show the trimmed means approach's ability to effectively estimate treatment efficacy when data are MNAR and missingness due to study discontinuation is strongly associated with an unfavorable outcome, but trimmed means fail when data are missing at random. If the reasons for study discontinuation in a clinical trial are known, analysts can improve estimates with a combination of multiple imputation and the trimmed means approach when the assumptions of each hold. We compare the methodology to existing approaches using data from a clinical trial for chronic pain. An R package trim implements the method. When the assumptions are justifiable, using trimmed means can help identify treatment effects notwithstanding MNAR data.     

Emotional decision-makers and anomalous attitudes towards information

We use a simple version of the Psychological Expected Utility Model (Caplin and Leahy, Q J Econ 116:55–80, 2001) to analyze the optimal choice of information accuracy by an individual who is concerned with anticipatory feeling. The individual faces the following trade-off: on the one hand information may lead to emotional costs, on the other the higher the information accuracy, the higher the efficiency of decision-making. We completely and explicitly characterize how anticipatory utility depends on information accuracy, and study the optimal amount of information acquisition. We obtain simple and explicit conditions under which the individual prefers no-information or partial information gathering. We show that anomalous attitudes towards information can be more frequent and articulated than previously thought.     

Pool size and the sustainability of optimal risk-sharing agreements

We study a risk-sharing agreement where members exert a loss-mitigating action which decreases the amount of reimbursements to be paid in the pool. The action is costly and members tend to free-ride on it. An optimal risk-sharing agreement maximizes the expected utility of a representative member with respect to both the coverage and the (collective) action such that efficiency is restored. We study the sustainability of the optimal agreement as equilibrium in a repeated game with indefinite number of repetitions. When the optimal agreement is not enforceable, the equilibrium with free-riding emerges. We identify an interesting trade-off: welfare generated by the optimal risk-sharing agreement increases with the size of the pool, but at the same time the pool size must not be too large for collective choices to be self-enforcing. This generates a discontinuous effect of pool size on welfare.     

International migrations and care provisions for elderly people left behind. The cases of the Republic of Moldova and Romania

International migrations are posing numerous challenges to care systems in both sending and receiving countries. Based on a multi-method research conducted between 2011 and 2013, this article looks at how the care provisions for elderly people are rearranged in two Eastern European countries affected by the care drain phenomenon (the Republic of Moldova and Romania). The author charts and compares how transnational families, but also the other facets of the care diamond, such as the public sector, the market and the not-for-profit sector, provide care to elderly people left to cope at home alone because their close relatives have migrated. The main findings of the article are that transnational families are the principal welfare provider for elderly people left behind, while there is a serious delay in the adoption of specific policies for the elderly.     

The Relation Between Participatory Social Practices and Social Representations of Citizenship in Young Adulthood

The concept of citizenship is used both as a synonym of social action when referencing to an active form of citizenship as well as to indicate a form of civic obligation (formal citizenship). According to these premises, citizenship can be formalized in a large number of activities that contribute to building it in different ways. The aim of the present work is to explore how the concepts of citizenship and being a citizen are co-built by Italian young adults. Two groups of young adults are considered (engaged vs. not engaged). Eighty-nine young adults participants aged 18–36 completed a self-administered mixed-method questionnaire. A content and thematic analysis was conducted and a composite representation of citizenship emerged. Results of the present work can clarify the concept of citizenship by exploring how it is cognitively and socially represented in young adults and how this representation changes in engaged and not engaged young adults.     

Urbanization drivers differentially affect ground arthropod assemblages in the city of Turin (NW-Italy)

Urban Ecosystems - Urbanization is a complex process associated with environmental changes affecting many biotic and abiotic ecosystem components, which cause the alteration of biological...     

Contending Stories: Narrative in Social Movements

Study of stories and storytelling in social movements can contribute to our understanding of recruitment that takes place outside formal movement organizations; social movement organizations' ability to withstand strategic setbacks; and movements' impacts on mainstream politics. This paper draws on several cases to illuminate the yields of such study and to provide alternatives to the overbroad, uncritical, and astructural understandings of narrative evident in some recent writings. It also urges attention to the role of literary devices in sociological analyses of collective action.