A Typology of Civilians Shot and Killed by US Police: a Latent Class Analysis of Firearm Legal Intervention Homicide in the 2014-2015 National Violent Death Reporting System.

Approximately 1000 people are killed by police acting in the line of duty each year. Historically, research on these deaths, known as legal intervention homicides (LIH), has been limited by data that is either contextually rich but narrow in scope and not readily available to the public (e.g., police department reports from a single city), or detail-poor but geographically broad, large, and readily available (and maintained by federal agencies) (e.g., vital statistics and supplemental homicide reports). Over the past 5 years, however, researchers have turned to the National Violent Death Reporting System (NVDRS), which captures nearly all lethal police shootings in participating states while providing detailed incident and victim information. The current study extends prior work on police-involved lethal shootings in three important ways. First, we use latent class analysis to construct a data-driven, exhaustive, mutually exclusive typology of these events, using NVDRS data 2014-2015. Second, rather than fitting some, but not all cases into predefined sub-types, every case is assigned membership to a particular emergent class. Third, we use a validated case identification process in NVDRS to identify incidents of lethal police-involved shootings. Seven classes emerge. Classes differ across important incident and victim characteristics such as the event that brought the victim and law enforcement together, the highest level of force used by the victim against law enforcement, and the kind of weapon, if any, used by the victim during the incident. Demographic variables do not distribute uniformly across classes (e.g., the latent class in which the victim appeared to pose minimal threat to law enforcement was the only class in which the plurality of victims was a non-white race). Our approach to generating these typologies illustrates how data-driven techniques can complement subjective classification schemes and lay the groundwork for analogous analyses using police encounter data that include fatal and non-fatal outcomes.

Speeds associated with skiing and snowboarding.

BACKGROUND/OBJECTIVE: Traumatic brain injury (TBI) is an important cause of morbidity and mortality in skiing and snowboarding. Although previous studies have advocated the use of a helmet to reduce the incidence of TBI, only a minority of skiers and snowboarders wear helmets. The low use of helmets may be partially due to controversy regarding their effectiveness in a high-speed crash. The protective effect of a ski helmet is diminished at the high speeds a skier or snowboarder can potentially obtain on an open slope. However, ski areas have undergone significant changes in the past decade. Many skiers and snowboarders frequent nontraditional terrain such as gladed areas and terrain parks. Since these areas contain numerous physical obstacles, we hypothesized that skiers and snowboarders would traverse these areas at speeds slow enough to expect a significant protective effect from a helmet. METHODS: Speed data were obtained via radar analysis of 2 groups of expert level skiers and snowboarders traversing a gladed woods trail and terrain park. RESULTS: A total of 113 observations were recorded. Forty-eight observations were made of 9 skiers and snowboarders in gladed terrain, and 65 observations were conducted of 21 skiers and snowboarders in the terrain park. In 79% of the cases in gladed terrain and 94% of the instances in the terrain park, observed speeds were less than 15 mph. CONCLUSIONS: Skiers and snowboarders navigate nontraditional terrain at speeds slower than on open slopes. At the observed velocities, a helmet would be expected to provide significant help in diminishing the occurrence of TBI. Medical authorities should advocate the use of helmets as an important component of an overall strategy to reduce the incidence of TBI associated with skiing and snowboarding.