Learning causal structure from mixed data with missing values using Gaussian copula models

We consider the problem of causal structure learning from data with missing values, assumed to be drawn from a Gaussian copula model. First, we extend the ‘Rank PC’ algorithm, designed for Gaussian copula models with purely continuous data (so-called nonparanormal models), to incomplete data by applying rank correlation to pairwise complete observations and replacing the sample size with an effective sample size in the conditional independence tests to account for the information loss from missing values. When the data are missing completely at random (MCAR), we provide an error bound on the accuracy of ‘Rank PC’ and show its high-dimensional consistency. However, when the data are missing at random (MAR), ‘Rank PC’ fails dramatically. Therefore, we propose a Gibbs sampling procedure to draw correlation matrix samples from mixed data that still works correctly under MAR. These samples are translated into an average correlation matrix and an effective sample size, resulting in the ‘Copula PC’ algorithm for incomplete data. Simulation study shows that: (1) ‘Copula PC’ estimates a more accurate correlation matrix and causal structure than ‘Rank PC’ under MCAR and, even more so, under MAR and (2) the usage of the effective sample size significantly improves the performance of ‘Rank PC’ and ‘Copula PC.’ We illustrate our methods on two real-world datasets: riboflavin production data and chronic fatigue syndrome data.

     

Existential Risks to Humanity Should Concern International Policymakers and More Could Be Done in Considering Them at the International Governance Level

In this perspective, we consider the possible role of the United Nations (UN) with respect to existential risks to human civilization and the survival of humanity. We illustrate how existential risks have been discussed at an international governance level, specifically in documents in the UN Digital Library. In this large corpus, discussions of nuclear war account for over two-thirds (69%, 67/97) of mentions of existential risks, while mention of other existential risks, or such risks as a category, appears scant. We take these observations to imply inadequate attention to these significant threats. These deficits, combined with the need for a global response to many risks, suggest that UN member nations should urgently advocate for appropriate action at the UN to address threats, such as artificial intelligence, synthetic biology, geoengineering, and supervolcanic eruption, in analogous fashion to existing attempts to mitigate the threats from nuclear war or near-Earth objects.     

Moving towards hybridity in causal explanation: The example of citizen participation

The puzzle of causal explanation is a core issue for social science. Searches for causal patterns can be overly mechanistic, seen for example in the desire for the magic bullet in policy, or the lionising of the celebrity policy interventions of the moment. Emphasis in policy interventions on transferable practice is often dismissed as naive for failing to recognise the importance of context, contingency, and complexity. However, a focus on highly context‐specific narratives, drawn from single cases, can be equally problematic and exacerbate rather than help the problem of reification of knowledge. This paper makes a reflective theoretical contribution to the debate on the need to tackle the dilemma of contingency versus certainty in causal explanation in the social sciences. It attempts to address this issue through the lens of a specific concrete puzzle of explanation; that of citizen participation in policy. Citizen participation is a salient policy topic, which demands a thorough understanding of causation. Using extended empirical examples of citizen participation in policy serves to highlight the intractability of different traditions of causal explanation and grounds the need for greater compatibility in approaches. The paper then offers two propositions centring on the notions of transdisciplinarity and hybridity in research practices and methodologies. It concludes with a discussion of more and less desirable forms of hybridity.     

THE “SALES AGENT” PROBLEM: EFFORT/LEISURE ALLOCATION UNDER PERFORMANCE PAY AS BEHAVIOR TOWARDS RISK

The choice between safe and risky assets represents behavior towards risk: more risk‐averse investors buy more safe assets. We develop and test a general model that applies this intuition to the time allocation between risky effort and risk‐free leisure under linear incentives. When risk increases with effort, risk‐averse agents choose less effort, but when risk is independent of effort, effort choice is unaffected by risk preferences. In many incentive contracts, income risk is multiplicative with, rather than additive to effort, sales commissions being one example. In such cases, lower effort by the risk‐averse is a hitherto undocumented behavior towards risk (JEL C91, M52, J33)     

The Protective Action Decision Model: Theoretical Modifications and Additional Evidence

The Protective Action Decision Model (PADM) is a multistage model that is based on findings from research on people's responses to environmental hazards and disasters. The PADM integrates the processing of information derived from social and environmental cues with messages that social sources transmit through communication channels to those at risk. The PADM identifies three critical predecision processes (reception, attention, and comprehension of warnings or exposure, attention, and interpretation of environmental/social cues)—that precede all further processing. The revised model identifies three core perceptions—threat perceptions, protective action perceptions, and stakeholder perceptions—that form the basis for decisions about how to respond to an imminent or long‐term threat. The outcome of the protective action decision‐making process, together with situational facilitators and impediments, produces a behavioral response. In addition to describing the revised model and the research on which it is based, this article describes three applications (development of risk communication programs, evacuation modeling, and adoption of long‐term hazard adjustments) and identifies some of the research needed to address unresolved issues.     

Toward a critical sociology of lifestyle migration: reconceptualizing migration and the search for a better way of life

This article places under critical and reflexive examination the theoretical underpinnings of the concept of lifestyle migration. Developed to explain the migration of the relatively affluent in search of a better way of life, this concept draws attention to the role of lifestyle within migration, alongside understandings of migration as one stage within the ongoing lifestyle choices and trajectories of individual migrants. Through a focus on two paradigms that are currently at work within theorizations of this social phenomenon – individualization and mobilities – we evaluate their contribution to this flourishing field of research. In this way, we demonstrate the limitations and constraints of these for understanding lifestyle migration; engaging with long‐standing debates around structure and agency to make a case for the recognition of history in understanding the pursuit of ‘a better way of life’; questioning the extent to which meaning is made through movement, and the politics and ethics of replacing migration with mobilities. Through this systematic consideration, we pave the way for re‐invigorated theorizing on this topic, and the development of a critical sociology of lifestyle migration.     

In bondage when cold was king: the frigid terrain of slavery in antebellum Maryland

Cold weather remains one of the least explored environmental phenomena in the historiography of American slavery. By detailing the heightened vulnerabilities of the enslaved during the colder portions of the year and then describing the means by which enslaved people leveraged frigid weather against slaveholders, this paper highlights how slave and slaveholder differently mobilized the cold against one another in contests over power. It argues that in the lives of enslaved women and men in antebellum Maryland, cold weather was both an afflicting as well as empowering force.     

Microstructures of economic action: talk,interaction and the bottom line

This paper contributes to an expanding body of research that has analysed the interactional foundations of economic activity, and price determination, by quantifying the financial implications of different micro‐interactional practices. Drawing on video recordings of naturalistic interaction the paper analyses a simple consumer choice, whether to pay one of two prices, the lower ‘standard’ price (£8.00) or the higher ‘gift aid’ (£8.80) price, to enter an arts institution. Utilizing resources from conversation analysis, the paper analyses different ways of posing this choice. It describes how, as interactional constraints tighten, standard prices become less socially desirable and customers increasingly ‘volunteer’ to pay the higher price. The paper contributes to sociological understandings of economic activity, demonstrating how simple one‐off choices, and prices, are accountably responsive to micro‐interactional structures.