Testing for covariate balance using quantile regression and resampling methods

Consistency of propensity score matching estimators hinges on the propensity score's ability to balance the distributions of covariates in the pools of treated and non-treated units. Conventional balance tests merely check for differences in covariates’ means, but cannot account for differences in higher moments. For this reason, this paper proposes balance tests which test for differences in the entire distributions of continuous covariates based on quantile regression (to derive Kolmogorov–Smirnov and Cramer–von-Mises–Smirnov-type test statistics) and resampling methods (for inference). Simulations suggest that these methods are very powerful and capture imbalances related to higher moments when conventional balance tests fail to do so.     

The bad and the ugly: ethical concerns in participatory photographic methods with children living and working on the streets of Lima,Peru

Visual methods are particularly well suited for getting at the ways in which children living and working on the street understand their socio-spatial environment, and can bridge gaps between researcher and researched. In this study, adolescents who live and work on the streets of Lima are asked to take photographs, documenting their lives and their socio-spatial environments. While participatory methods such as photovoice can bring children and adolescents into the research process and can provide significant benefits to research and its participants, the introduction of photographic methods with marginalised populations carries with it important ethical concerns. This article explores the various critiques of documentary photography, and ethical concerns that arise when using visual methods, including issues of exploitation and intrusion in research with adolescents living on the streets. It also examines the ways in which researchers must continuously reassess their methodological practices in order to protect the best interests of the participants involved.     

Impact of urban structure on avian diversity along the Truckee River, USA

Urban riparian habitats are potentially important resources for native birds in arid ecosystems. Most studies have assessed the value of urban riparian habitat in terms of vegetation and natural resources; however, the surrounding land use and infrastructure may determine the viability of urban habitat. We studied the impact of urban structure, the combination of land use, infrastructure and vegetation variables that work together to shape the urban environment, on avian riparian habitat in the Truckee Meadows, Nevada, USA. Land use and infrastructure explained avian species richness and abundance better than local vegetation alone, but community resemblance was more strongly correlated to vegetation. Avian species guilds responded differentially to surrounding land use, suggesting there may be a functional difference between land use types. The best models for bird diversity used urban structure (both land use and vegetation) to describe potential habitat. Urban structure describes urban habitat in ways that vegetation variables alone cannot. Studies that ignore land use and infrastructure and other socioeconomic variables are likely missing key functional differences within urban ecosystems, and may miss the potential for compatible development that encourages both biodiversity and urban growth.     

Least Absolute Regression Revisited

We describe a method for fitting a least absolute residual (LAR) line through a set of two–dimensional points. The algorithm is based on a labeling technique derived from linear programming. It is suited for interactive data analysis and can be carried out with graph paper and a programmable hand calculator. Tests conducted with a Pascal program indicate that the algorithm is computationally efficient.     

Women and the Wild: Gender Socialization in Wilderness Recreation Advertising

Women are underrepresented in wilderness recreation despite the numerous benefits such activities provide to mental, physical, and emotional health. Several theories have been proposed linking women??s beliefs about their competence in outdoor spaces, fears of victimization, and concerns over retaining femininity to their lack of participation. We explore media representations of wilderness recreation as a possible agent in the gender socialization process that dissuades women from participation. Through analyzing advertisements from the 42 issues of Backpacker and Outside magazines published in 2008 and 2009 we find that, when women are shown, they are portrayed as having limited and passive roles in wilderness recreation. These advertisements also use the setting to reinforce traditional gender arrangements and paint women as consumers rather than conquerors of the wild. When women are shown as active participants in wilderness recreation, their physical accomplishments are often either downplayed or depicted as the endeavors of ??unique?? women who require feminization.     

Do actions reduce perceived risk? A longitudinal analysis of the relationship between risk perception and actions in response to forest disturbance in Colorado

As residents living in hazard-prone areas face on-going environmental threats, the actions they take to mitigate such risks are likely motivated by various factors. Whereas risk perception has been considered a key determinant of related behavioral responses, little is known about how risk mitigation actions influence subsequent perceived risk. In other words, do actions to prevent or mitigate risk reduce risk perception? This longitudinal study considers the dynamic relationships between risk perception and risk-mitigating behavior in the context of forest disturbance in north-central Colorado. Based on panel survey data collected in 2007 and 2018, the results provide a first look at changes in perceived forest risks as they relate to individual and community actions in response to an extensive mountain pine beetle outbreak. Analysis revealed that the perception of direct forest risks (forest fire and falling trees) increased, whereas indirect forest risk perception (concern on broader threats to local community) decreased across the two study phases. Higher individual or community activeness (level of actions) was associated with subsequent reductions in perceived forest fire risk, smaller increases in direct risk perception, and larger decreases in indirect risk perception. These findings contribute insights into the complex risk reappraisal process in forest hazard contexts, with direct implications for risk communication and management strategies.     

Screening for recommended antenatal risk factors: How long does it take?

Background

Detection and management of antenatal risk factors is critical for quality care.

Measuring active living in Canada: A time-use perspective

In Canada there is an increasing prevalence of chronic medical conditions and diseases related to a modifiable risk factor - physical inactivity. Therefore, it is important to have regular, robust, population-based surveillance of physical activity engagement that can be used to develop policy interventions and measure their success. The primary objective of this study is to describe the methods used to quantify the proportion of Canadians engaging in physical activities at the intensities and durations required to either maintain or enhance their health. Results indicate the overall proportion of Canadians meeting maintenance levels of physical activity has increased between 1992 (76.2%), 1998 (77.3%), and 2005 (82.5%), but over the same time the proportion meeting enhancement levels of physical activity has decreased (38.1%, 36.6%, and 30.6%, respectively). Furthermore, the results demonstrate the potential applications of time-use data for public health and quality of life research.     

Appetite for Destruction? China,Ecologically Unequal Exchange,and Forest Loss

We test the hypothesis from the theory of ecologically unequal exchange that agricultural exports to China are related to increased forest loss in low- and middle-income nations exporting to it. We do so by analyzing data for 75 low- and middle-income nations using ordinary least squares regression. We find support for our hypothesis that flows of agricultural exports from low- and middle-income nations to China are related to increased forest loss in exporting nations. We also find that a country's total agricultural exports, proximity of forest to infrastructure, and protected areas tend to increase forest loss.     

Adaptive Shrinkage in Bayesian Vector Autoregressive Models

Vector autoregressive (VAR) models are frequently used for forecasting and impulse response analysis. For both applications, shrinkage priors can help improving inference. In this article, we apply the Normal-Gamma shrinkage prior to the VAR with stochastic volatility case and derive its relevant conditional posterior distributions. This framework imposes a set of normally distributed priors on the autoregressive coefficients and the covariance parameters of the VAR along with Gamma priors on a set of local and global prior scaling parameters. In a second step, we modify this prior setup by introducing another layer of shrinkage with scaling parameters that push certain regions of the parameter space to zero. Two simulation exercises show that the proposed framework yields more precise estimates of model parameters and impulse response functions. In addition, a forecasting exercise applied to U.S. data shows that this prior performs well relative to other commonly used specifications in terms of point and density predictions. Finally, performing structural inference suggests that responses to monetary policy shocks appear to be reasonable.