One of the many statistics that Emergency Manager Kevyn Orr used to support Detroit's filing for Chapter 9 bankruptcy was a shocker that quickly made international news: Detroit police take an average of 58 minutes to respond to emergency calls, compared with a national average of 11 minutes.
That stat played a central role in a little-noticed article Aug. 2 in the Wall Street Journal's Numbers Guy Blog in which reporter Carl Bialik dissects the 58-minute response and talked to James Craig, the newly hired Detroit police chief.
Craig told Bialik that part of what makes Detroit seem so tardy is the way it classifies calls. Bialik writes:
"...one reason the stats make his officers seem so slow to arrive is that his department puts far more calls than other departments into the high-priority category—about 50%. He said his staff has examined the subset of calls that were true emergencies and found that response times last year averaged 15 minutes. He added that the time included the period between when the 911 call was answered and when it was assigned to a police unit, time that some departments don't count and that Detroit's won't count in the future.
"It's not that we want to play with the numbers," Chief Craig said. "It's just that we want to make sure we calculate it the same way everyone else does it."
Looking at the bigger picture, Bialik writes that even Detroit's 58-minute response times "say little about the effectiveness of the city's police, according to law-enforcement experts and former and current police chiefs."
"There is no standard way, they say, for cities to measure response times, which can vary according to many factors: how many calls are labeled high-priority and included in the average; whether unusually long waits for police response are tossed from the data set; whether the clock starts when a 911 call is answered by an operator or when the call is dispatched to the police; and whether officers check in promptly after arriving at a crime scene."
Even if response times were standardized, Bialik writes, they wouldn't be the most important indicator of police performance, say law-enforcement scholars. The vast majority of calls—those when the crime has already been committed and the perpetrator has left the scene—don't require an immediate response. What matters more, according to several studies, is whether callers are given an accurate estimate of arrival time, and what officers accomplish when they do arrive.
Bialik couldn't find the source for the 11-minute national average. A spokeswoman for Gov. Rick Snyder cited Orr's report to creditors, and an Orr spokesman didn't respond to a request to provide sources for the estimate. Law-enforcement scholars said they doubted a national average is available, given the dearth of standardized data.