Since 2016, Utah law has mandated that any public school or library applying for state money must provide filtering software on its computers to prevent access to child pornography and other obscene material on the internet.

A new study from the United Kingdom suggests the filtering technology isn’t up to the job.

The study, conducted by researchers at the University of Oxford, finds that such filters are “entirely ineffective” at keeping young people from getting to online porn and similar material.

“There is little empirical evidence that Internet filters provide an effective means to limit children’s and adolescents' exposure to online sexual material,” said the study, written by researchers Andrew K. Przybylski and Victoria Nash at the Oxford Internet Institute. It was published July 1 in the journal Cyberpsychology, Behavior and Social Networking.

State Sen. Todd Weiler, R-Woods Cross, has advocated for laws to combat pornography — he sponsored a resolution to declare porn a “public health crisis” — but he said technological fixes are no match for good parenting.

( Al Hartmann | The Salt Lake Tribune ) Sen. Todd Weiler, R- Woods Cross and Rep. Craig Hall, R-West Valley City, left, stand with representatives of anti-pornography groups and Gov. Gary Herbert at the ceremonial signing of two pornography bills, SCR-9 and HB 155.

“I don’t think there’s any substitute for having that conversation with your kids,” Weiler said. “I don’t think there’s a silver bullet.”

Weiler earned national press when he explored the idea of requiring filtering software on all mobile phones. He said he dropped the idea because it was “clearly a violation of the First Amendment.”

Utah is one of 25 states with laws mandating schools or libraries or both to develop policies to protect children from offensive material online, according to the National Council of State Legislatures. Twelve of those states, including Utah, require filtering software as part of that solution.

This year, the Legislature passed and Gov. Gary Herbert signed into law a requirement that internet service providers notify customers that the providers can block pornography or other material “harmful to minors.” Providers have until year’s end to conform to the new law.

Though he has not looked at the Oxford study’s methodology, Weiler said he’s unsurprised that young people would try to thwart filtering software.

“Whenever you tell people you can’t see [something], it’s obviously going to become taboo and increase people’s desire to want to see it,” Weiler said. “That’s just human nature.”

Internet filters have been in place in the Salt Lake City Library system for a couple of years, said Andrew Shaw, the library’s communications manager. Though the city considered going without state funding, ultimately it put in the filtering software to conform to the Utah Legislature’s wishes.

“With a library of our size, we have a little leeway to make that decision,” Shaw said. “For a smaller library, they don’t have that option.”

At the Salt Lake City Library, software from a Boston-based company, iboss, allows different settings for the computers used by adults than the ones used by children. For adults, filters block child pornography, adult porn and nudity, malware and viruses, and proxies. The children’s computers have filters that block all of those, plus sites dealing with alcohol, tobacco, drugs, violence, hate, dating and personals, and the umbrella term “adult content.”

The study’s authors noted that internet filters “are costly to develop and maintain.” Also, filters often fail by not blocking enough, letting offensive material slip through, or by blocking too much, “restricting access to necessary health, cultural and social information.”

That problem is one the American Library Association, which advocates for the nation’s libraries, has warned against for years.

“Basically, the study confirms what the ALA has been arguing from the beginning,” said James LaRue, director of the ALA’s Office for Intellectual Freedom.

“There is underblocking, so the filters won’t stop people if they’re determined,” LaRue said, adding that some filters “also overblock. They block access to things that have nothing to do with pornography.”

Some topics that might be blocked by an overly sensitive filter, the study’s authors noted, include medical information and resources for LGBTQ teens.

“Those topics that are the most sensitive and most important are the ones that fall victim to the filter,” Shaw said.

The best line of defense against offensiveness in a library is a good librarian, LaRue said. “When we find out someone is misbehaving in public, you say, ‘Excuse me, could you behave yourself?’"