Report: School web filters can block some health sites

The way schools, libraries, and parents apply filtering software to block pornographic and controversial web sites can have a “large impact” on students’ access to health-related information, according to a new study by health researchers.

The study found that filtering software set to a “moderately restrictive” blocking level—commonly found in schools and libraries—blocked three times as many health sites as the least restrictive setting. While only 5 percent of more than 3,000 health sites were blocked in the study, the software blocked on average 27 percent of sites specifically about condoms and 20 percent of sites about safe sex, an impact on web surfers that researchers described as “modest.”

“A teenager whose access to a particular health information site is inadvertently blocked will probably be able to easily find an unblocked site with similar information,” said the study, called “Does Pornography-Blocking Software Block Access to Health Information on the Internet?” and published in the Dec. 11 issue of The Journal of the American Medical Association.

The study also found that software filters, which can be adjusted in intensity, can be fooled: They commonly block more internet sites associated with terms like “safe sex” or “condoms” than web pages a person might find while searching for information about “birth control” or “herpes.”

Researchers set out to determine whether internet filters inadvertently block access to useful health information, because teenagers increasingly rely on the internet for answers to health-related questions.

More than 70 percent of 15- to 17-year-olds say they have used the internet to look up health information such as cancer, diabetes, pregnancy, birth control, sexually transmitted diseases, or sexual assault. Teenagers without computers at home tend to rely on school and library computers for internet access, the study said.

Researchers tested software from six different companies—SmartFilter, 8e6 Technologies, Websense, SurfControl, Symantec, and N2H2—along with AOL Parental Controls. At least-aggressive levels, filtering software prevented researchers from viewing 1.4 percent of health sites surveyed and 9 percent of sites specifically about sexual health. The study’s supporters said that as the level of blocking increased, more health sites were blocked than additional pornography sites.

The study offered a surprising lift for the handful of U.S. companies producing oft-maligned filtering software. Civil libertarians frequently complain about these programs because they arbitrarily block categories of internet sites that some find offensive but others might find helpful.

“The message is, a little filtering is probably OK,” said Victoria Rideout, a vice president at the Henry J. Kaiser Family Foundation, a philanthropic group that publishes some sexual health information on the web and sought to find out how much of its work was inaccessible to students and library patrons. Kaiser paid $200,000 for the study.

Congress in 2000 required internet filters in schools and libraries that accept federal funding, but a U.S. appeals panel in Philadelphia last year ruled that part of the Children’s Internet Protection Act (CIPA) violates the First Amendment because filters also can block sites on politics, health, and science. The appeals-panel ruling applied only to public libraries. CIPA would remain in force for schools, unless the ruling were expanded. The Supreme Court has said it will decide the issue by next summer.

While the study seems to say filters are doing an OK job, critics point out that it also found that filters aren’t foolproof.

“They seem to have found that filters block 87 percent of objectionable material. If I were a parent, I wouldn’t be that excited about 87 percent. What about the other 13 percent that isn’t blocked?” said Emily Sheketoff, executive director of the American Library Association’s Washington, D.C., office.

“The Kaiser study demonstrates the reasons why it is both unwise and inappropriate to place reliance on filtering software to protect young people when they are using the internet,” said Nancy Willard, a research associate at the University of Oregon’s Center for Advanced Technology in Education.

“In those categories where the subject area is controversial or the sites themselves may contain controversial information, the rate of overblocking was significantly higher. The categories that stood out included safe sex, homosexuality, and drugs,” Willard said.

At most-restrictive levels, designed to block access to racism, hateful speech, or sites about violence or gambling, filtering software blocked 24 percent of health sites and 50 percent of sites specifically about sexual health, the study found.

“The problem seems to be, when you get into blocking all these categories, a lot of youthful, mainstream information gets blocked,” Rideout said.

At the least restrictive settings, 10 percent of sites with the terms “safe sex,” “condom,” or “gay” were blocked. For other keyword searches, only 1 percent of health sites were blocked.

In the least restrictive category, Websense was least likely to block health information, and N2H2 was a close second, the researchers said.

Sites blocked by some software filters at their most restrictive settings included a web page with facts about genital herpes from the U.S. Centers for Disease Control and Prevention, and a federal guide to birth control from the U.S. Food and Drug Administration. Software from one company, Symantec Corp., blocked a fact sheet about herpes from the National Institutes of Health, even at its least restrictive settings.

One of the study’s authors, Dr. Caroline Richardson of the University of Michigan Medical School, predicted that some software filters probably would block access to web pages with details from this research.

Richardson said filtering software on public computers in schools and libraries can discourage research on health issues by people who need it most.

“People who are least likely to have access to the internet at home are also at highest risk for some of the medical problems they might be able to get information about on the internet,” she said. “The internet is a way to disseminate accurate and easy-to-access information in a timely manner. If that access if blocked, it’s not clear that everybody will find the information some other way.”


Henry J. Kaiser Family Foundation

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