THE MOST disturbing experience I’ve had in some time was a visit to a state government website.

On the screen was a list of all the dangerous sex offenders who live or work near my house. All I had to do was enter my zip code, and a list of profiles popped up. For each, a criminal history was displayed in stomach-turning legalese - “indecent assault and battery on child under 14 years of age.’’ The offender head shots were even more alarming: some appeared openly deranged, others vacant, but all had the distinct aura of pure evil.

The profiles are posted online as part of a national effort, nearly two decades old, to warn the public about sex offenders. The registries are expanding, and some states are moving to track other types of criminals. You can even get an iPhone app that shows offender addresses. This is an effort I have always supported. I have kids. But recent research suggests that publishing the personal details of sex offenders is not only ineffective, but could lead to more sex crimes.

Our current policy of publicizing personal information about offenders is rooted in two particular cases. In 1989, an 11-year-old boy named Jacob Wetterling was kidnapped at gunpoint by a masked man in Minnesota. Jacob has never been found, and the crime never solved, but it inspired a federal law that requires states to set up registries to track certain classes of criminals, including sex offenders.

Then in 1994, a 7-year-old New Jersey girl was lured into a house by a neighbor who offered to show her a puppy. The neighbor, a convicted sex offender, then raped and murdered her. The case inspired “Megan’s Law’’ in New Jersey and a federal provision requiring states to publicize details on released sex offenders.

The rationale is straightforward: People who have been warned can take precautions. Crimes will be prevented.

Yet a 2008 study of New Jersey, sponsored by the National Institute of Justice, found no evidence that the measure reduced sex crimes and suggested that “the growing costs may not be justifiable.’’

Now an even more ambitious pair of studies, published in the Journal of Law and Economics, suggests notification laws are an empty comfort.

One study of 49 states found that posting sex offender information on the Internet had no effect on the incidence of rape. Another analysis took the home addresses of all the sex offenders living in Washington, D.C., and compared them with reports of sexual abuse. The researcher, Amanda Agan of the University of Chicago, found no correlation. A sex offender on the block doesn’t affect the crime rate. Or, put another way, knowing that a sex offender lives nearby tells the public nothing about the actual risk of a sex crime.

The second study found that public notification laws do serve as a deterrent, slightly reducing the number of first-time sexual offenders. That makes sense: Nobody would want their photo and personal details published that way.

However, public notification can also bring an even larger increase in recidivism. Putting a person on a public registry, with their photo and home address, subjects them to harassment and makes it more difficult for them to reintegrate into society - to find and keep a job, or find a place to live. Small punishment, you might say, given the crimes. But the effect, starkly put, is to reduce the rewards for living honestly. On average, write the scholars J.J. Prescott and Jonah Rockoff, public notifications increase sex offenses by about 1.6 percent, and the effect worsens as more criminals are included.

The question we must answer is, what do we want for these people, after they have been released? There is an emotional response, of course: a life of everlasting punishment. Then there is a more reasoned one: do whatever it takes to minimize the chance of more crimes. We should follow the evidence, however counterintuitive or distasteful it might seem. There are former sex offenders living in your midst, and it’s better you not know where they live.

Gareth Cook can be reached at cook@globe.com. Follow him on Twitter @garethideas.

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