New Haven experienced a massive 21 percent decrease in reported crime last year, and the city has seen crime fall by over 50 percent since 1990, according to the city’s recently released Uniform Crime Report data for 2000.

Mayor John DeStefano Jr. and Police Chief Melvin H. Wearing have attributed the city’s continuing success in fighting crime to the New Haven Police Department’s continued emphasis on community policing, instituted in the early 1990s.

“Over the past decade, the changes the department has undergone along with our community partnerships have helped New Haven to become a safer city,” Wearing said.

Among other reforms, the NHPD created community substations in an effort to make the department more accessible to citizens. It also works with a number of government and private organizations, such as the Livable City Initiative and the Yale Child Study Center.

And the numbers back up the touted successes of these programs. Both violent and property crime rates have decreased markedly over the last 10 years — from 3,991 to 1,694 and from 17,021 to 7,761, respectively.

Last year, crime decreased nearly across the board, although the one negative number that pops out of the 2000 statistics is the number of murders, always a high-profile bellwether. There were 18 homicides in New Haven in 2000, compared with only 12 in 1999.

The existence of brief murder spikes, which can drive up numbers quickly, is clear. In January 2001, for example, five homicides were committed in New Haven. There have been none in the month and a half since.

DeStefano has repeatedly said these spikes may be unexplainable.

The annual crime reports, which every police organization in the country must file with the FBI, lists the numbers of murders, rapes, robberies, assaults, burglaries, larcenies and automobile thefts.

Most Connecticut communities have yet to finish compiling the 2000 crime data, and state and national compilations are likely months away.

But New Haven’s success does contrast strongly with last year’s crime statistics in Hartford, which saw a 10 percent increase in reported crimes after years of decreases. The two cities have similar populations and police departments focused on community policing.

The New Haven Police Department itself has been a model for agencies across the country seeking to adopt the community policing model.

That model, along with improved economic conditions, helped make the 1990s a time of significant advances in crime fighting nationwide, although other less obvious factors may have played a large role.

“A lot of it typically has to do with age demographics, so the number of young people in a population can affect crime rates,” said Jon’a Meyer, a professor of sociology and criminal justice at Rutgers University. “If you have demographic changes, you should expect crime rates to change with those.”

Even what seem to be large trends in crime rates, like the successes of the 1990s, may just be part of a long-term cycle.

“If you look at crime overall, in particular if you include a larger slice of time, you’ll see that it does fluctuate up and down,” Meyer said.

Nationwide, crime decreased only 1.3 percent through the first six months of 2000, the latest data available from the FBI. Whether that means further successes are in store or that the national crime rate has plateaued depends on which expert you ask, Meyer said.