While apparently aimed at Mayor Bill de Blasio, the two-week slowdown also prompted questions about Mr. Bratton and how much control he and his leadership team had over the tens of thousands of officers and traffic agents who are the public faces of the Police Department. No one had publicly urged a slowdown, yet in all 77 police precincts, activity sharply declined. Citywide, arrests fell by half and criminal and traffic summonses dropped more than 90 percent.

At the same time, by focusing on activity numbers, Mr. Bratton found himself forced to do the very thing that critics — including officers and their unions — had declared a prime problem with the previous police administration. Mr. Bratton sought to quickly distinguish his order, however, saying it was about quality arrests, not officers reaching a certain quantity of activity for a given week or month.

“There is no specific target number that we go for,” Mr. Bratton said on Monday. “There are no quotas, if you will.”

The sharp drop began after Officers Wenjian Liu and Rafael Ramos were shot to death in their patrol car on Dec. 20, targeted by a man who sought to kill police officers and committed suicide minutes later. Almost immediately, the Police Department ordered extra precautions, ending solo foot patrols and adding protection at precinct stations. Union officials went further, telling their members to put their own safety first on the street.

The killings ripped open a rift between the police unions and City Hall that had festered for most of last year, though union leaders denied any effort to encourage officers to stop working. They pointed out that officers continued to respond to 911 calls and highlighted the shooting of two officers who were responding to a robber in the Bronx.

Liberal critics of the Police Department’s practices — particularly its “broken windows” focus on low-level crimes — seized on the sharp reduction of such arrests during the slowdown as evidence that the aggressive approach was not necessary. Crime did not spike during the slowdown, the critics noted, even as officers curtailed their focus on low-level offenses across the city.