Police union leaders said the database included false allegations and frivolous lawsuits that could be used to help defendants who are guilty to undermine the credibility of police witnesses at trial.

“The intent of this database is clearly to help guilty criminals beat the charges against them,” Patrick Lynch, the Patrolmen’s Benevolent Association president, said in an email. “By publishing this database online, they will be doing even greater damage: Anyone with a grudge against cops will be free to peruse the false and frivolous allegations against specific officers and use them as inspiration for a campaign of harassment, intimidation or worse.”

Many officers regard the roughly 3,000 lawsuits filed each year against the police as a cottage industry. They argue that in too many cases, people with flimsy complaints sue, knowing the city will find it cheaper to settle than to take the case to trial.

New York law prohibits the release of results of internal police investigations, deeming them personnel records. Judicial findings about officers who commit perjury are difficult to collect since they are not centrally recorded or archived. As a result, civil suits against officers are one of the few public, though imperfect, measures that can be used to gauge police misconduct, public defenders said.

The Police Department said in an email that “not all lawsuits filed for money have legal merit.”

“The ones that do can be valuable tools we use to improve officer performance and enhance training or policy where necessary,” the department said.

The lawsuits in the CAPstat database are public records taken from federal and state court websites. The database will include lawsuits that were dismissed or settled out of court. It will also incorporate four years of internal disciplinary records leaked to Buzzfeed News last year, even though those records are confidential under state law.

Joanna Schwartz, a professor of law at the University of California, Los Angeles, who studies misconduct suits, said the CAPstat database could also be used by the police and city officials to identify problematic officers and units.