Understanding Community Resilience from a PRA Perspective Using Binary Decision Diagrams

Probabilistic risk assessment (PRA) is a useful tool to assess complex interconnected systems. This article leverages the capabilities of PRA tools developed for industrial and nuclear risk analysis in community resilience evaluations by modeling the food security of a community in terms of its built environment as an integrated system. To this end, we model the performance of Gilroy, CA, a moderate‐size town, with regard to disruptions in its food supply caused by a severe earthquake. The food retailers of Gilroy, along with the electrical power network, water network elements, and bridges are considered as components of a system. Fault and event trees are constructed to model the requirements for continuous food supply to community residents and are analyzed efficiently using binary decision diagrams (BDDs). The study also identifies shortcomings in approximate classical system analysis methods in assessing community resilience. Importance factors are utilized to rank the importance of various factors to the overall risk of food insecurity. Finally, the study considers the impact of various sources of uncertainties in the hazard modeling and performance of infrastructure on food security measures. The methodology can be applicable for any existing critical infrastructure system and has potential extensions to other hazards.     

Designing out vulnerability, building in respect: violence, safety and sex work policy

One recent finding about the prostitution market is the differences in the extent and nature of violence experienced between women who work on the street and those who work from indoor sex work venues. This paper brings together extensive qualitative fieldwork from two cities in the UK to unpack the intricacies in relation to violence and safety for indoor workers. Firstly, we document the types of violence women experience in indoor venues noting how the vulnerabilities surrounding work-based hazards are dependent on the environment in which sex is sold. Secondly, we highlight the protection strategies that indoor workers and management develop to maintain safety and order in the establishment. Thirdly, we use these empirical findings to suggest that violence should be a high priority on the policy agenda. Here we contend that the organizational and cultural conditions that seem to offer some protection from violence in indoor settings could be useful for informing the management of street sex work. Finally, drawing on the crime prevention literature, we argue that it is possible to go a considerable way to designing out vulnerability in sex work, but not only through physical and organizational change but building in respect for sex workers rights by developing policies that promote the employment/human rights and citizenship for sex workers. This argument is made in light of the Coordinated Prostitution Strategy.     

Modeling population and subject-specific growth in a latent trait measured by multiple instruments over time using a hierarchical Bayesian framework

Psychometric growth curve modeling techniques are used to describe a person’s latent ability and how that ability changes over time based on a specific measurement instrument. However, the same instrument cannot always be used over a period of time to measure that latent ability. This is often the case when measuring traits longitudinally in children. Reasons may be that over time some measurement tools that were difficult for young children become too easy as they age resulting in floor effects or ceiling effects or both. We propose a Bayesian hierarchical model for such a scenario. Within the Bayesian model we combine information from multiple instruments used at different age ranges and having different scoring schemes to examine growth in latent ability over time. The model includes between-subject variance and within-subject variance and does not require linking item specific difficulty between the measurement tools. The model’s utility is demonstrated on a study of language ability in children from ages one to ten who are hard of hearing where measurement tool specific growth and subject-specific growth are shown in addition to a group level latent growth curve comparing the hard of hearing children to children with normal hearing.KEYWORDS: Bayesian hierarchical models, psychometric modeling, language ability, growth curve modeling, longitudinal analysis     

Risking safety and rights: online sex work,crimes and ‘blended safety repertoires’

It has been well established that those working in the sex industry are at various risks of violence and crime depending on where they sell sex and the environments in which they work. What sociological research has failed to address is how crime and safety have been affected by the dynamic changing nature of sex work given the dominance of the internet and digital technologies, including the development of new markets such as webcamming. This paper reports the most comprehensive findings on the internet‐based sex market in the UK demonstrating types of crimes experienced by internet‐based sex workers and the strategies of risk management that sex workers adopt, building on our article in the British Journal of Sociology in 2007. We present the concept of ‘blended safety repertoires’ to explain how sex workers, particularly independent escorts, are using a range of traditional techniques alongside digitally enabled strategies to keep themselves safe. We contribute a deeper understanding of why sex workers who work indoors rarely report crimes to the police, reflecting the dilemmas experienced. Our findings highlight how legal and policy changes which seek to ban online adult services advertising and sex work related content within online spaces would have direct impact on the safety strategies online sex workers employ and would further undermine their safety. These findings occur in a context where aspects of sex work are quasi‐criminalized through the brothel keeping legislation. We conclude that the legal and policy failure to recognize sex work as a form of employment, contributes to the stigmatization of sex work and prevents individuals working together. Current UK policy disallows a framework for employment laws and health and safety standards to regulate sex work, leaving sex workers in the shadow economy, their safety at risk in a quasi‐legal system. In light of the strong evidence that the internet makes sex work safer, we argue that decriminalisation as a rights based model of regulation is most appropriate.     

Service diversification and growth of professional service firms

This study investigates the impact of service diversification on the rate and mode of firm growth in professional service firms (PSFs). Drawing on the extant PSF literature, we identify differing views regarding the growth impact of service diversification. Specifically, some scholars suggest that the external client benefits associated with service diversification should allow PSFs to expand revenues at a rapid pace and pursue less merger and acquisition activity, whereas others imply that increased diversification can cause internal challenges with respect to learning costs, coordination and innovation that can limit the rate of revenue growth and encourage more mergers and acquisitions. We test these competing views using longitudinal data on 137 accounting firms and cross-sectional data on 125 law firms and find that service diversification is negatively associated with the rate of firm revenue growth and positively associated with the use of mergers and acquisitions.     

Harm reduction for cannabis: Factor analysis of a protective behavioral strategies survey

Objective: To examine the psychometric properties of a measure of cannabis-specific Protective Behavioral Strategies (PBS), which assesses ways in which students may reduce cannabis-related risk. Participants: Respondents to the American College Health Association – National College Health Assessment II (N = 580) during Spring 2015. Methods: Exploratory Factor Analysis (EFA) and Exploratory Structural Equation Modeling (ESEM) were used to identify and replicate the factor structure of the measure. Results: Results support a four-factor model (Respiratory Health, Frequency/Quantity, Socializing, and General Health) with close approximate fit (Χ² (310) = 565.96, p < .001, RMSEA = .038 (.033, .043; 90% CI), CFI = .961, TLI = .929, SRMR = .033). Support for the convergent validity and construct validity of the measure was also found. Conclusions: This is the initial step in the development of a standard, psychometrically validated measure of cannabis PBS that has the potential to inform future research and interventions.