By John Sullivan, Liz Weber, Julie Tate and Jennifer Jenkins | Washington Post
Fatal shootings by police are the rare outcomes of the millions of encounters between police officers and the public. Despite the unpredictable events that lead to the shootings, in each of the past four years police nationwide have shot and killed almost the same number of people – nearly 1,000.
Last year police shot and killed 998 people, 11 more than the 987 they fatally shot in 2017. In 2016, police killed 963 people, and 995 in 2015.
Years of controversial police shootings, protests, heightened public awareness, local police reforms and increased officer training have had little effect on the annual total. Everyone agrees – criminal justice researchers, academics and statisticians – that all of the attention has not been enough to move the number.
Mathematicians, however, say that probability theory may offer one explanation. The theory holds that the quantity of rare events in huge populations tends to remain stable absent major societal changes, such as a fundamental shift in police culture or extreme restrictions on gun ownership, which are unlikely.
“Just as vast numbers of randomly moving molecules, when put together, produce completely predictable behavior in a gas, so do vast numbers of human possibilities, each totally unpredictable in itself, when aggregated, produce an amazing predictability,” said Sir David Spiegelhalter, a professor and statistician at the University of Cambridge who studies risk and uncertainty.
The Washington Post began tracking the shootings after Michael Brown, an unarmed black man, was killed in 2014 by police in Ferguson, Missouri. A Post investigation found that the FBI’s tracking system undercounted fatal police shootings by about half, because of the fact that reporting by police departments is voluntary and many departments fail to do so. The ongoing Post project relies on news accounts, social media postings and police reports.
In the wake of the findings by The Washington Post and similar reporting by the Guardian, the FBI in 2015 committed to improving its tracking and last month launched a system to track all police use-of-force incidents, including fatal shootings. The new system, however, is still voluntary.
The Post’s reporting shows that both the annual number and circumstances of fatal shootings and the overall demographics of the victims have remained constant over the past four years.
The dead: 45 percent white men; 23 percent black men; and 16 percent Hispanic men. Women have accounted for about 5 percent of those killed, and people in mental distress about 25 percent of all shootings.
About 54 percent of those killed have been armed with guns and 4 percent unarmed.
“We’ve looked at this data in so many ways, including whether race, geography, violent crime, gun ownership or police training can explain it, but none of those factors alone can explain how consistent this number appears to be,” said Geoffrey Alpert, a criminologist at the University of South Carolina who has studied police shootings for more than three decades.
Mathematicians say that the fact that the number of shootings is stable even though each one …read more
Source:: The Mercury News – Health