More than 5,300 violent assaults have been misreported since 2006, Milwaukee Police Chief Edward Flynn told a Common Council committee Thursday.

An internal department audit shows that 20% of aggravated assaults were underreported as lesser offenses that didn't get counted in the city's violent crime rate during that time.

That echoes the findings of a Journal Sentinel investigation last month of a more-limited pool of cases that identified in excess of 500 misreported serious assaults over a three-year period and another 800 cases that fit the same pattern.

The department's review suggests the problem is much deeper than had been reported and has existed for a longer period, including before Flynn's tenure began in 2008.

Flynn said the assault coding errors identified by the department will be sent to the FBI for revision, which will place the city's overall crime rate higher than previously reported.

The department's review also determined that almost 1,200 minor crimes were over-reported during the past six years. Over-reporting means those cases should have been classified as lesser crimes, Flynn said.

Flynn and other police officials speaking Thursday said that despite thousands of crime coding errors in both directions, their review showed violent crime is still down by double digits - a 25% decrease since 2007.

Flynn stressed the errors were due to human and computer error and not the result of any manipulation of data.

"There is a big difference between a bureaucratic failure and a bureaucratic plot," Flynn said. "There has been a bureaucratic failure, and to the extent I'm the chief bureaucrat, I'm responsible for that failure.

"The bottom line is, counting that bureaucratic failure into our crime data, the fact remains that the work of our officers has had an impact on crime and that impact has been favorable over the last six years."

Based on the numbers provided by the department to aldermen Thursday, the under-coding error rate was 23% in the two years before Flynn came to Milwaukee, compared with 19% since his arrival in 2008.

After the police report to the Public Safety Committee, aldermen voted to delay a final vote on a proposal that would direct the city comptroller's office to conduct an outside audit of the department's crime numbers.

When the FBI reviews crime data reported by states, the goal is to find less than a 2% error rate for all crimes, said Daniel Bibel, former president of the Association of State Uniform Crime Reporting Programs. An under-reporting error rate of 20% for aggravated assaults is 10 times higher than the accepted standard.

"This is the highest error rate I have ever heard of," said Samuel Walker, criminology professor at the University of Nebraska-Omaha. "A genuinely independent audit of the department is necessary."

Mayor Tom Barrett praised the department for being transparent about flaws in crime data.

"While there were errors in total crimes reported to the FBI, the Police Department's analysis shows crime trends previously reported are correct," Barrett said. "Milwaukee is a safer city."

Newspaper review

The initial request for Flynn's testimony came after the Journal Sentinel found hundreds of serious assaults were misclassified by the department as minor offenses over the past three years. The review also found more than 800 additional cases that fit the same pattern but couldn't be verified with available public records.

The Journal Sentinel is seeking copies of the 828 incident reports that match the pattern through an open records request. Flynn last week said he wants more than $10,000 in fees before copying and redacting the records. That's more than twice as much as the department sought two years ago for 750 reports, a request the Journal Sentinel is fighting in court.

Dozens of misclassified assaults were sent to FBI crime reporting experts, who confirmed they should have been marked as aggravated assaults, which are counted in the city's violent crime rate. Police officials agreed that a sample of assault cases shared by the Journal Sentinel were misreported as minor offenses.

Errors in crime classification don't change how cases are handled by prosecutors. Records indicate many of the perpetrators were convicted of their crimes.

Last week, a Journal Sentinel review found that Milwaukee police record clerks have routinely changed computer codes by hand in a way that removes serious assaults from the city's violent crime rate. Department officials acknowledged this was happening, blaming it on training issues.

Several aldermen, including Jim Bohl, Robert Puente and Joe Davis Sr., criticized the Journal Sentinel's coverage of the issue. Specifically, they said they did not like the implications in the stories that police may be manipulating crime data.

"Nobody is doing this purposely - misreporting crimes," Puente said. "With this subject matter coming out the way it did, when it did … is putting doubt into the people of this city of what a great job the Milwaukee Police Department is doing, especially under the command of this chief. And I resent it totally."

Ald. Bob Donovan praised the newspaper's investigation for bringing crime reporting errors to light.

"I'm pretty certain that we would not have even been there today discussing admitted failures and shortcomings in our crime reporting system if it wasn't for the efforts of Journal Sentinel," Donovan said in an interview.

Larger review coming

After the initial Journal Sentinel findings, Flynn said his department would conduct an internal audit and share its findings with the Milwaukee Fire and Police Commission and the public. Besides the targeted review of thousands of assault reports released Thursday, police said they will also conduct a more comprehensive review of all crime categories.

Also, Milwaukee police last year requested that FBI auditors include the department in a regular statewide audit of crime reporting that was conducted in May. The results of that audit, which included eight other police agencies in the state, won't be released until fall.

The sample used in the periodic FBI audits typically covers hundreds of reports. The Journal Sentinel's investigation compared crime data to some 60,000 cases, which amounted to more than one-fifth of the 280,000 reported crimes in the period covered. Only the cases sent to prosecutors could be reviewed based on available data.

In voting 4-1 to hold the proposal directing the City Comptroller's office to audit the crime-reporting practices, committee members said they would prefer to wait until the department's final comprehensive audit, as well as the FBI audit, is completed.

Ald. Joe Dudzik was the primary sponsor of the resolution, which was co-sponsored by aldermen Donovan, Bohl, Jose Perez and Davis.

The council voted 13-1 last week to send the resolution to the committee to get more details about the proposed audit, including a cost estimate and information about who would conduct the review.

Some council members suggested the city may have to hire an outside consultant with the expertise to conduct such an audit, given the department's role as the largest law enforcement agency in the state.