TRENTON - A federally funded study on Megan's Law in New Jersey has found that it does not deter first-time sex offenders or help prevent convicted sex offenders from re-offending.

The study is one of a limited number nationwide to empirically examine the impact of sex-offender registration and notification laws such as Megan's Law, which now can be found in every state.

The study's authors found that while sexual-offense rates have trended downward in New Jersey since 1994, the decrease cannot be attributed to Megan's Law. They also found that Megan's Law has had no significant effect on the length of time before a sex offender's first rearrest, the type of first-time sexual offense or re-offense, or on the overall number of victims involved in sexual offenses.

"It didn't change the type of offense that offenders committed when they did commit crimes, and it didn't change the number of victims," said Kristen Zgoba of the New Jersey Department of Corrections Research and Evaluation Unit, who was the principal investigator on the study.

The study, released Thursday, concludes that there is little evidence, despite the popularity of the sex-offender notification laws, that they are effective. The authors recommend that if further research confirms their findings, policymakers should consider alternative steps to reduce sex-offense rates, such as "mandated treatment of all sex offenders, potential use of polygraph testing, and intensive probation and parole supervision."

Philip Witt, a psychologist and the co-principal investigator of the study, said Megan's Law can "cut both ways."

On the one hand, some people may take better precautions to protect their children if they know there is a sex offender in the neighborhood. On the other hand, such laws can stigmatize sex offenders, placing them under greater stress, which can contribute to repeat offenses.

"In the end, both could happen and it's a wash, and the result is there's no change in the rate," Witt said.

Witt, who helped New Jersey implement Megan's Law, said sex-offender notification laws should be much more thoroughly researched to determine their effectiveness. But he is not ready to discount the laws.

"I'm not saying repeal it. I'm not saying it doesn't work," Witt said.

Megan's Law was named after Megan Kanka, a 7-year-old New Jersey girl who was raped and killed in 1994 by a convicted sex offender who lived in her neighborhood.

Kanka's mother, Maureen Kanka, says the laws were never intended to alter the behavior of sex offenders.

"It was to provide an awareness to the public, which it has done," Kanka said yesterday. "We never said it would stop them from going somewhere else and sexually abusing." She added: "Would having that knowledge have made a difference for my daughter? Absolutely. She'd have been alive and well."

Sen. Bill Baroni (R., Mercer) also said the study "completely misses the objective of Megan's Law."

Baroni said the law is a "tool that parents and other adults responsible for the welfare of children can utilize to ensure that every necessary measure is being used to safeguard children from an identified threat."

"Any attempt to use this study to weaken or erode Megan's Law will never succeed," added Baroni, who grew up and lives in Hamilton, Megan Kanka's hometown.

Instead, Baroni called for the Legislature to explore ways to keep predators off the streets, including longer prison terms, civil commitment, and electronic monitoring.

The study estimated the cost of implementing Megan's Law in 15 counties that responded to a survey to be $3.97 million per year, mostly attributed to additional staffing costs.

The study was funded by the National Institute of Justice and underwent four blind reviews through the institute, the authors said.

Under Megan's Law, when sex offenders move into a neighborhood, they must register on an Internet registry available to the public. For the sex offenders considered the most dangerous, police go door-to-door to notify residents.

Recent studies on sexual offender notification laws in New York and Arkansas reached similar conclusions.