NYPD Commissioner Bill Bratton stepped down this afternoon, following the announcement last month that he'd accepted a post as executive chairman of risk management for an international consulting firm. The outgoing top cop rounded out his tenure with a strong defense of Broken Windows—the controversial theory that aggressive policing of low-level violations reduces crime overall.

A Department of Investigation study cut against this assumption in June. Reviewing arrest data from the last six years, investigators found no correlation between the rate of misdemeanor summonses and arrests, and that of felony crime. The report also reinforced a major critique of the practice: that it continues to be disproportionately applied against African-American and Hispanic New Yorkers.

Bratton commissioned an internal critique of the report, concluding that the study period was too narrow to reveal Broken Windows' true impact. "Believe me, I think I know what I'm doing," he said last week. "Broken Windows and quality-of-life policing have been integral to the changes this city has seen since the 1990s, and the changes we've seen over the past two and a half years."

Speaking on The Brian Lehrer Show this morning, Mayor de Blasio praised Bratton, as he often has, for doing "more than anyone in the history of this city to make the city safer." The soon-to-be former commissioner has been a large proponent of CompStat crime data-tracking, briefing the press once a month on the percentage peaks and dips in various arrests: for shootings, robberies, assaults, thefts, etc. Last week, the NYPD dubbed summer 2016 the safest of any in the CompStat era, dating back to 1994.

De Blasio went on to call Broken Windows "quality-of-life policing that helped us to address the problem of disorder that was plaguing us for decades," adding:

It constantly has to be updated. And it must be applied fairly and consistently across all communities. There is more to do to make Broken Windows a better strategy, but it is still the right approach.

A small group of protesters gathered behind police barriers near Commissioner Bratton's farewell ceremony on Friday to critique his legacy, which they said was defined by arrests for minor infractions like turnstile jumping, and inadequate punishment for police officers who injure and kill civilians.

Towards the end of Bratton's tenure, the City Council voted to decriminalize several quality of life offenses. However, the new regulations preserve NYPD officers' ability to make arrests as they deem appropriate. "The rights, responsibilities, and capabilities of my police officers don't change at all," Bratton told WNYC recently, adding, "My officers still have the right to make an arrest if the behavior is egregious or inappropriate."

Advocates and City Council members were surprised in July, when Council Speaker Melissa Mark-Viverito tabled a vote on a police reform bills with wide support. The bills would compel police officers to get consent before searching people's homes when they lack a warrant or probable cause, and to identify themselves and explain their reasons for stops.

Bratton has called these and other police reform bills "unprecedented intrusions" on police work. Today, in a New York Times op-ed, he made a case for leaving police reform to the police.

"There are police reformers from outside the profession who think that changing police culture is a matter of passing regulations, establishing oversight bodies and more or less legislating a new order," he said. "It is not."

Bratton's successor is James O'Neill, formerly Chief of Patrol and a proponent of neighborhood policing, which sets aside designated time for beat cops to talk with people who live and work in their precincts. Under this strategy, cops are not assessed solely on the number of arrests they make.

Last week, O'Neill backed up Bratton's defense of Broken Windows. "This is a tool that we have to keep using,” he said.