Because of a statistical manipulation, Chief Cathy Lanier’s Metropolitan Police Department reported an impressive 94 percent homicide closure rate for 2011. But by artificially inflating its success, MPD is exaggerating how much safer the city has gotten during Lanier’s tenure, and in effect betraying the trust of the public. The artifice is especially puzzling in light of the fact D.C.’s violent crime rate has dropped in real terms during Lanier’s tenure.
Homicide closure rates are meant as administrative tools rather than scientific gauges of success. MPD uses the FBI’s Uniform Crime Reporting system, which calculates the rate by dividing the number of cases solved by the number of offenses closed in a year, and dividing that by the number of crimes committed during that same year. But federal regulation on the system is lax, so police departments across the country report varying statistics. Lanier’s department was counting cases opened in previous years and closed in 2011, but not taking into account crimes from previous years that remain unsolved.
This kind of statistical manipulation was first used in the 1980s when the District’s closure rate started to decline. At that point, MPD adopted the FBI’s UCR system—which allows for this statistical manipulation—to make it appear that they were solving more homicides than they actually were.
Under this statistical stratagem, a department could boast a success rate of over 100 percent. Furthermore, a 94 percent closure rate is, as former FBI special agent Brad Garrett told the Post, an unrealistic goal in the District. He also elaborated on alternative methods for calculating closure rates. “If the case is from 1994, then you say that the rate includes X cases from 1994, X cases from 1996 and so on. That way it’s clear that it’s a combination from other years.”
As Lanier has pointed out, this practice predates her time as Chief of Police. However, it is also not unprecedented for a Chief to alter the way the Department calculates its statistics. Former D.C. police captain W. Louis Hennessy, who oversaw the homicide unit from 1993 to 1995, called the then-current method “entirely unfair.” When he came into MPD, he changed the system to the format Special Agent Garrett suggested.
In all, it is a bit puzzling that MPD would risk such a scandal when the real violent crime rate has been dropping in real terms since Lanier’s arrival while the real closure rate rises. Even so, D.C. still struggles with its reputation as a violent city, and mismanagement like this only increases doubts about community safety as a whole.
It is clearly dishonest to continue employing these statistics in a city where the police chief is tantamount to a political figure. It’s true Lanier has an approval rating to keep up. But her inflated homicide closure rate might be inflating that as well.