Excellent article about it from City Journal by Heather Mac Donald.

An excerpt.

The campaign to deny the murder and shooting spike in many American cities continues apace. The latest effort is a report by the Brennan Center for Justice, which the press has hailed ecstatically as a refutation of what I and others have dubbed the “Ferguson effect”—the phenomenon of officers backing off of proactive policing and thereby emboldening criminals. In fact, the report confirms the Ferguson effect, while also showing how clueless the media are about crime and policing.

The Brennan Center researchers gathered homicide data from 25 of the nation’s 30 largest cities for the period January 1, 2015, to October 1, 2015. (Not included were San Francisco, Indianapolis, Columbus, El Paso, and Nashville.) The researchers then tried to estimate what 2015’s full-year homicide numbers for those 25 cities would be, based on the extent to which homicides were up from January to October 2015, compared with the similar period in 2014.

The resulting projected increase for homicides in 2015 in those 25 cities is 11 percent. (By point of comparison, the FiveThirtyEight data blog looked at the 60 largest cities and found a 16 percent increase in homicides by September 2015. On Monday, the Brennan Center revised its own estimate of the 2015 murder increase to 14.6 percent.) An 11 percent one-year increase in any crime category is massive; an equivalent decrease in homicides would be greeted with high-fives by politicians and police chiefs. Yet the media have tried to repackage that 11 percent increase as trivial. They employ several strategies for doing so, the most important of which is simply not disclosing the actual figure. An Atlantic article titled “Debunking the Ferguson Effect” reports: “Based on their data, the Brennan Center projects that homicides will rise slightly overall from 2014 to 2015.” A reader could be forgiven for thinking that that “slight” rise in homicides is of the order of, say, 2 to 3 percent. Nothing in the Atlantic write-up disabuses the reader of that error. Vox, declaring the crime increase “bunk,” is similarly discreet about the actual homicide jump, leaving it to the reader’s imagination. Crime & Justice News, published by the John Jay College of Criminal Justice, coyly admits that “murder is up moderately in some places” without disclosing what that “moderate” increase may be.

A second strategy for brushing off the homicide surge is to contextualize it over a long period of time. Because homicides haven’t returned to their early 1990s or early 2000s levels, the current crime increase is insignificant, the Brennan Center and its media supporters assert, echoing an argument that arose immediately after I first documented the Ferguson effect nationally. “Today’s murder rates are still at all-time historic lows,” write the Brennan Center researchers. “In 1990 there were 29.3 murders per 100,000 residents in these cities. In 2000, there were 13.8 murders per 100,000. Now, there are 9.9 murders per 100,000 residents. Averaged across the cities, we find that while Americans in urban areas have experienced more murders this year than last year, they are safer than they were five years ago and much safer than they were 25 years ago.” The Atlantic is similarly reassuring: “The relative uptick [which he never specifies] is still small compared to the massive two-decade drop [in homicides] that preceded it.”

It’s unlikely, however, that the nation would give back in one year a 50 percent crime drop that unfurled over two decades. The relevant question is: What is the current trend? If 2015’s homicide and shooting outbreak continues, those 1990s violent-crime levels will return sooner than anyone would have imagined. Violent crime was down nearly 5 percent in the first half of 2014; the post-Ferguson violent-crime spike in the second half of 2014 wiped out that earlier crime success, leaving 2014 a wash. Since then, crime has continued rising.

The most desperate tactic for discounting the homicide increase is to disaggregate the average. Yes, some cities have seen a homicide increase, the Ferguson-effect deniers argue, but others have seen a homicide decrease. “Fears of ‘a new nationwide crime wave’ are premature at best and wildly misleading at worst,” asserts The Atlantic, because the “numbers make clear that violent crime is up in some major U.S. cities and down in others.” But such variance is inherent in any average. If there weren’t variation across the members of a set, no average would be needed. Any national crime increase or decrease will have counterexamples of the dominant trend within it, yet policymakers and analysts rightly find the average meaningful. The existence of a Ferguson effect does not require that every city experience de-policing and a resulting crime increase. Enough cities are, however—in particular, those with significant black populations and where antipolice agitation has been most strident—to demand attention.

The Brennan Center takes one more stab at underplaying the homicide increase: looking at crime overall. It projects that in 19 cities, the 2015 average for all seven of the FBI’s index crimes—murder, rape, robbery, aggravated assault, burglary, larceny, and car theft—will be 1.5 percent less than in 2014. The FBI’s crime index is dominated by property crimes, which outnumber offenses committed against persons. Proponents of the Ferguson effect have argued that it is violent crime, not theft, that is responding to de-policing. Proactive stops and low-level misdemeanor enforcement deter gun-carrying and interrupt retaliatory gang shootings by intervening in suspicious behavior before it ripens into a violent felony. Career burglars are less affected by whether a cop is willing to get out of his car and question someone hitching up his waistband on a known drug corner at 1 AM. That property crimes have not spiked to the same extent in response to de-policing is no refutation of the claim that violent crimes have.

Ferguson-effect deniers would have you believe that the nation’s law-enforcement officials are in the grip of a delusion that prevents them from seeing the halcyon crime picture before their eyes. Since summer 2015, police chiefs have been sounding the alarm about violent crime. In August, the Major Cities Chiefs Association convened an emergency session to discuss the homicide and shooting surge. In early October, Attorney General Loretta Lynch brought together more than 100 mayors, police leaders, and U.S. attorneys to strategize privately over the violent-crime increase. Attendees broke out in applause when mayors attributed the increase to officers’ sinking morale, according to the Washington Post. “Most of America’s 50 largest cities have seen an increase in homicides and shootings this year, and many of them have seen a huge increase,” FBI director James Comey noted at the end of October. Two weeks later, the acting chief of the Drug Enforcement Administration, Chuck Rosenberg, seconded Comey’s crime analysis as well as Comey’s hypothesis that the backlash against the police was likely responsible for that violent-crime increase.