TUESDAY, Dec. 10, 2002 (HealthDayNews) -- Filters that shield children from Internet pornography can be tuned to let most health information pass through. However, some topics such as condoms and homosexuality are much more likely than others to be blocked no matter how loose the screening, a new study has found.
The study, by researchers at the University of Michigan and the Kaiser Family Foundation, found that at their least restrictive settings the software nannies block only about 1 percent or so of health-related Web sites. However, as the restrictions increase to include the widest range of topics such as nudity and violence, the share of health sites blocked climbs to nearly a quarter.
"The bottom line is that the settings that you choose in the software determine how good it is at blocking out objectionable material," says Dr. Caroline R. Richardson, a family medicine specialist at the University of Michigan and lead author of the study.
In fact, Richardson says, poor spelling and badly organized Web pages are far bigger hurdles to accessing health information efficiently on the Internet than are filtering systems at their least intrusive.
Yet as the screening settings tighten benign topics frequently fall victim to censorship, and some search terms are far more likely than others to draw the attention of filters no matter how weakly they're set. A report on the findings appears in tomorrow's issue of the Journal of the American Medical Association.
Richardson and her colleagues evaluated seven filtering programs in Web searches for both health and pornography on six popular Internet search engines. The health topics ranged from things wholly unrelated to sex, such as diabetes, to controversial subjects such as abortion. The searches ignored advertisements.
The laxest screening blocked an average of 1.4 percent of legitimate health sites, while filtering 87 percent of pornographic pages. On the medium setting, 5 percent of health sites were rejected, and the porn control rose to nearly 90 percent. And at the tightest setting, 24 percent of health sites were blocked, along with 91 percent of porn pages.
Not only was the finest filter the most restrictive of health information, but it had a hard time discriminating sex-free material from questionable pages. The strict screening blocked nearly 14 percent of links for diabetes diets, the researchers found, along with 10 percent of those for diabetes.
Even on the least restrictive settings, some information was much more likely to raise alarms. The weak filters blocked access to 10 percent of sites relating to condoms, safe sex and homosexuality. In the most restrictive mode that figure rose to between 50 percent and 60 percent. "Then you're starting to get into numbers that block access completely," Richardson says.
The U.S. Supreme Court last month agreed to consider the constitutionality of the 2000 Children's Internet Protection Act, which cuts off government funds to public libraries that don't install filters. Last May, a panel of federal judges in Philadelphia struck down the law as an infringement on free speech rights.
The American Library Association, the American Civil Liberties Union and others sued the government over the law. Judith Krug, director of the ALA's office for intellectual freedom, says the latest study confirms her group's research showing that filters block too much unobjectional material while letting porn slip by. Although the 1.4 percent figure seems small, Krug says, "the truth is that when you start looking at the numbers of pages involved it gets very substantial."
Chris Hansen, a lawyer for the American Civil Liberties Union, says low error rates don't reflect the magnitude of censorship that can occur with an Internet filter. Blocking even one site accidentally can prevent tens of thousands of people from viewing it each year, he says.
Only about 2 percent of the several billion Web pages currently online contain sexually explicit material, Krug says. Much of that isn't pornography, but rather health sites dealing with testicular and breast cancer, breast-feeding and other topics with words that filters flag. "When you're talking about mechanical devices, you're talking about things that have no judgment," she says.
Will Doherty, a spokesman for the Electronic Frontier Foundation, a San Francisco civil liberties group devoted to defending "digital rights," says it will be "many years" before blocking software is advanced enough to police the Internet effectively while sparing material that's not offensive. A new study by the foundation and the Online Policy Group found that filters in schools misclassify as many as third to half of Web pages.
The 2000 law applies to both libraries and schools, though the Supreme Court case involves only libraries. Hansen, who is also executive director of the Online Policy Group, said open Internet advocates may challenge the academic portion of the bill if the high court strikes down the library part.
What To Do
For more on Internet filters, try the American Library Association or the American Civil Liberties Union. Read about the Children's Internet Protection Act provisions at the Colorado Department of Education.
