The District's 94% homicide clearance rate is not what it seems
Washington D.C. reported a 94-percent homicide clearance rate for 2011. A clearance rate is the number of homicides committed and the number of homicides solved in a given year. Contrast D.C.'s numbers with Baltimore's, police closed 65 of the 196 homicides reported in 2011, a true closure rate of 33 percent. The national homicide clearance rate was about 65 percent in 2010, based on the multilayer totals reported to the FBI's Uniformed Crime Report, as reported by The Washington Post.
A closer examination of D.C.'s homicides found that the department’s closure rate is a statistical mishmash that makes things seem much better than they are. The District had 108 homicides last year, police records show. A 94 percent closure rate would mean that detectives solved 102 of them. But only 62 were solved as of year’s end, for a true closure rate of 57 percent, according to records reviewed by The Washington Post. D.C. police achieved the high closure rate last year by including about 40 cases from other years that were closed in 2011.
Police referred reporters to the FBI’sUniform Crime Reporting Web page. A separate FBI publication on law enforcement records says only that a clearance rate is calculated by dividing the number of offenses cleared by the number of offenses known. Each year, police departments across the country send their crime statistics to the FBI’s UCR Program, reporting the number of crimes that occurred in a year and the number that were closed — or solved — in that year. But the numbers are not necessarily connected to each other: Crimes cleared in one year might have occurred in another.
The manipulation of clearance rates is nothing new in D.C. The Washington Post looked back at the clearance rate for the four years prior to 2011:
D.C. police are fudging the statistics to give citizens a false sense of security. The D.C. police are touting an enormously successful clearance rate of 94 percent which is more than nine out of ten murders solved. In reality D.C. is solving six out of ten.
Homicide has long been considered the most trust worthy crime statistic. A police department had to report a homicide for what it was, a violent death. A homicide could not be reported as an assault in the same manner a shooting without death could be changed to a disorderly conduct.
However, D.C. has proven that police departments can even be creative with homicide statistics.
To read more: http://www.washingtonpost.com/investigations/the-trick-to-dc-police-forces-94percent-closure-rate-for-2011-homicides/2012/01/30/gIQATErbMR_story.html