Shooting Down the More Guns, Less Crime Hypothesis

John Lott and David Mustard have used regression analysis to argue forcefully that 'shall-issue' laws (which give citizens an unimpeded right to secure permits for concealed weapons) reduce violent crime. While certain facially plausible statistical models appear to generate this conclusion, more refined analyses of more recent state and county data undermine the more guns, less crime hypothesis. The most robust finding on the state data is that certain property crimes rise with passage of shall- issue laws, although the absence of any clear theory as to why this would be the case tends to undercut any strong conclusions. Estimating more statistically preferred disaggregated models on more complete county data, we show that in most states shall- issue laws have been associated with more crime and that the apparent stimulus to crime tends to be especially strong for those states that adopted in the last decade. While there are substantial concerns about model reliability and robustness, we present estimates based on disaggregated county data models that on net the passage of the law in 24 jurisdictions has increased the annual cost of crime slightly -- somewhere on the order of half a billion dollars. We also provide an illustration of how our jurisdiction-specific regression model has the capacity to generate more nuanced assessments concerning which states might profit from or be harmed by a particular legal intervention.

Importance of long-term cycles for predicting water level dynamics in natural lakes

Lakes are disproportionately important ecosystems for humanity, containing 77% of the liquid surface freshwater on Earth and comprising key contributors to global biodiversity. With an ever-growing human demand for water and increasing climate uncertainty, there is pressing need for improved understanding of the underlying patterns of natural variability of water resources and consideration of their implications for water resource management and conservation. Here we use Bayesian harmonic regression models to characterise water level dynamics and study the influence of cyclic components in confounding estimation of long-term directional trends in water levels in natural Irish lakes. We found that the lakes were characterised by a common and well-defined annual seasonality and several inter-annual and inter-decadal cycles with strong transient behaviour over time. Importantly, failing to account for the longer-term cyclic components produced a significant overall underestimation of the trend effect. Our findings demonstrate the importance of contextualising lake water resource management to the specific physical setting of lakes

Regression of ranked responses when raw responses are censored

We discuss semiparametric regression when only the ranks of responses are observed. The model is $Y_i = F (\mathbf{x}_i'{\boldsymbol\beta}_0 + \varepsilon_i)$, where $Y_i$ is the unobserved response, $F$ is a monotone increasing function, $\mathbf{x}_i$ is a known $p-$vector of covariates, ${\boldsymbol\beta}_0$ is an unknown $p$-vector of interest, and $\varepsilon_i$ is an error term independent of $\mathbf{x}_i$. We observe $\{(\mathbf{x}_i,R_n(Y_i)) : i = 1,\ldots ,n\}$, where $R_n$ is the ordinal rank function. We explore a novel estimator under Gaussian assumptions. We discuss the literature, apply the method to an Alzheimer's disease biomarker, conduct simulation studies, and prove consistency and asymptotic normality.Comment: 33 pages, 6 figure

Shooting Down the More Guns, Less Crime Hypothesis

In a remarkable paper published in 1997, John Lott and David Mustard managed to set the agenda for much subsequent dataset work on the impact of guns on crime in America by creating a massive dataset of crime across all U.S. counties from 1977 through 1992 and by amassing a powerful statistical argument that state laws enabling citizens to carry concealed handguns had reduced crime. The initial paper was followed a year later by an even more comprehensive and sustained argument to the same effect in a book solely authored by John Lott entitled More Guns, Less Crime (now in its second edition). The work by Lott and Mustard has triggered an unusually large set of academic responses, with talented scholars lining up on both sides of the debate. Indeed, a panel of the National Academy of Sciences has been convened to sort through the now large body of conflicting studies. But in the world of affairs rather than ideas, it did not take long for the National Rifle Association (NRA) and politicians across the country to seize upon the work of Lott and Mustard to oppose efforts at gun control and advance the cause of greater freedom to carry guns. For example, in the same year that the initial article was published, Senator Larry Craig (R-Idaho) introduced The Personal Safety and Community Protection Act, which was designed to facilitate the carrying of concealed firearms by nonresidents of a state who had obtained valid permits to carry such weapons in their home state. Senator Craig argued that the work of John Lott showed that arming the citizenry via laws allowing the carrying of concealed handguns would have a protective effect for the community at large because criminals would find themselves in the line of fire. On May 27, 1999, Lott testified before the House Judiciary Committee that the stricter gun regulations proposed by President Clinton either would have no effect or would actually cost lives, and a number of Republican members of Congress have since included favorable references in their speeches to Lott\u27s work. Moreover, Lott has also testified in support of concealed gun laws before several state legislatures, including Nebraska (1997), Michigan (1998), Minnesota (1999), Ohio (2002), and Wisconsin (2002)

Posner\u27s Third Symphony: Thinking about the Unthinkable

In the 100th year following the death of Franz Liszt, Richard Posner has published the third edition of his own classic work, The Economic Analysis of Law. This coincidence is in some sense fitting, for, in many respects, what Liszt was to the piano and musical composition, Posner is to legal scholarship and public policy. Just as Liszt was the dominant figure in the creation of the modem pianist, Posner has presided over the rise of law and economics in the domain of legal scholarship. Just as everyone concedes that Liszt demonstrated immense talent in performing his own and others\u27 music, no one disputes Posner\u27s abilities as an outstanding scholar and expositor of his own and others\u27 economic analyses of legal issues

Measuring resilience is essential to understand it

The terms sustainability, resilience and others group under the heading of ‘stability’. Their ubiquity speaks to a vital need to characterize changes in complex social and environmental systems. In a bewildering array of terms, practical measurements are essential to permit comparisons and so untangle underlying relationships

Integrating multiple dimensions of ecological stability into a vulnerability framework

Ecological stability encompasses multiple dimensions of functional and compositional responses to environmental change. Though no single stability dimension used in isolation can fully reflect the overall response to environmental change, a common vulnerability assessment that integrates simultaneously across multiple stability components is highly desirable for ecological risk assessment. We develop both functional and compositional counterparts of a novel, integrative metric of overall ecological vulnerability (OEV). We test the framework with data from a modularized experiment replicated in five lakes over two seasons, examining functional and compositional responses to both pulse and press disturbances across three trophic groups. OEV is measured as the area under the curve integrated over the entire observation period, with the curve delimiting the difference between the disturbance treatment and undisturbed parallel controls, expressed either as the log response ratio of biomass (functional OEV) or community dissimilarity index (compositional OEV). Both, functional and compositional OEV correlated negatively with functional and compositional 'resistance', 'temporal stability' and 'final/extent of recovery' following both pulse and press disturbances, though less so with 'resilience' following a pulse disturbance. We also found a positive correlation between functional and compositional OEV, which reveals the potential to also evaluate the intricate linkage between biodiversity and functional change. Our findings demonstrate that OEV comprises a robust framework to: (a) capture simultaneously multiple functional and compositional stability components, and (b) quantify the functional consequences of biodiversity change. Our results provide the basis for an overarching framework for quantifying the overall vulnerability of ecosystems to environmental change, opening new possibilities for ecological risk assessment and management. Synthesis. Ecological stability comprises multiple dimensions that together encapsulate how ecosystems respond to environmental change. Considering these multiple aspects of stability simultaneously often poses a problem in environmental assessments, which frequently require overarching indicators of risk or vulnerability. While an analysis of multiple dimensions allows for deeper exploration of mechanisms, here we develop and test a new univariate indicator that integrates stability aspects under a broad range of disturbance regimes. Using a modularized experiment in Swedish lakes, we show that this integrative measure captures multiple stability dimensions reflecting compositional and functional vulnerability and their relationships between them

Utility of acoustic indices for ecological monitoring in complex sonic environments

With the continued adoption of passive acoustic monitoring as a tool for rapid and high-resolution ecosystem monitoring, ecologists are increasingly making use of a suite of acoustic indices to summarise the sonic environment. Though these indices are often reported to well represent some aspect of the biology of an ecosystem, the degree to which they are confounded by various extraneous sonic conditions is largely unknown. We conducted an aural inventory across 23 field sites in Okinawa to identify the number of unique animal sounds present in recordings. Using these values of \u27measured richness\u27, we then examined how the performance of 11 commonly-used acoustic indices varied across a range of sonic conditions (including in the presence and absence of insect stridulation, audible wind or rain, and human-related sounds). Our analysis identified both well- and poor-performing acoustic indices, as well as those that were particularly sensitive to sonic conditions. Only two indices reflected measured richness across the full range of sonic conditions examined. A few indices were relatively insensitive to extraneous sonic conditions, but no index correlated with measured richness when masked by sound from broadband stridulating insects. Our results demonstrate considerable sensitivity of most commonly used acoustic indices to confounding sonic conditions, highlighting the challenges of working with large acoustic datasets collected in the field. We make practical recommendations for acoustic index use based on study design, with the aim of identifying the suite of acoustic indices with greatest utility as indicators for rapid biodiversity monitoring and management of the world\u27s natural soundscapes

Nothing lasts forever: Dominant species decline under rapid environmental change in global grasslands

1. Dominance often indicates one or a few species being best suited for resource capture and retention in a given environment. Press perturbations that change availability of limiting resources can restructure competitive hierarchies, allowing new species to capture or retain resources and leaving once dominant species fated to decline. However, dominant species may maintain high abundances even when their new environments no longer favour them due to stochastic processes associated with their high abundance, impeding deterministic processes that would otherwise diminish them. 2. Here, we quantify the persistence of dominance by tracking the rate of decline in dominant species at 90 globally distributed grassland sites under experimentally elevated soil nutrient supply and reduced vertebrate consumer pressure. 3. We found that chronic experimental nutrient addition and vertebrate exclusion caused certain subsets of species to lose dominance more quickly than in control plots. In control plots, perennial species and species with high initial cover maintained dominance for longer than annual species and those with low initial cover respectively. In fertilized plots, species with high initial cover maintained dominance at similar rates to control plots, while those with lower initial cover lost dominance even faster than similar species in controls. High initial cover increased the estimated time to dominance loss more strongly in plots with vertebrate exclosures than in controls. Vertebrate exclosures caused a slight decrease in the persistence of dominance for perennials, while fertilization brought perennials' rate of dominance loss in line with those of annuals. Annual species lost dominance at similar rates regardless of treatments. 4. Synthesis. Collectively, these results point to a strong role of a species' historical abundance in maintaining dominance following environmental perturbations. Because dominant species play an outsized role in driving ecosystem processes, their ability to remain dominant—regardless of environmental conditions—is critical to anticipating expected rates of change in the structure and function of grasslands. Species that maintain dominance while no longer competitively favoured following press perturbations due to their historical abundances may result in community compositions that do not maximize resource capture, a key process of system responses to global change.EEA Santa CruzFil: Wilfahrt, Peter A. University of Minnesota. Department of Ecology, Evolution, and Behavior; Estados UnidosFil: Seabloom, Eric William. University of Minnesota. Department of Ecology, Evolution, and Behavior; Estados UnidosFil: Bakker, Jonathan D. University of Washington. School of Environmental and Forest Sciences; Estados Unidos.Fil: Biederman, Lori A. Iowa State University. Department of Ecology, Evolution, and Organismal Biology; Estados UnidosFil: Bugalho, Miguel N. University of Lisbon. Centre for Applied Ecology “Prof. Baeta Neves” (CEABN-InBIO). School of Agriculture; Portugal.Fil: Cadotte, Marc W. University of Toronto Scarborough. Department of Biological Sciences; Canadá.Fil: Caldeira, Maria C. University of Lisbon. Forest Research Centre. School of Agriculture; Portugal.Fil: Catford, Jane A. King’s College London. Department of Geography; Reino UnidoFil: Catford, Jane A. University of Melbourne. School of Agriculture, Food and Ecosystem Sciences; Australia.Fil: Chen, Qingqing. Peking University. College of Urban and Environmental Science; China.Fil: Chen, Qingqing. German Centre for Integrative Biodiversity Research (iDiv). Halle-Jena-Leipzig; AlemaniaFil: Donohue, Ian. Trinity College Dublin. School of Natural Sciences. Department of Zoology; IrlandaFil: Peri, Pablo Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Santa Cruz; Argentina.Fil: Peri, Pablo Luis. Universidad Nacional de la Patagonia Austral.; Argentina.Fil: Peri, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Borer, Elizabeth T. University of Minnesota. Department of Ecology, Evolution, and Behavior; Estados Unido