Why Filters Won't Protect Children or Adults

by Nancy Kranich

Published in  Library Administration & Management, vol. 18, number 1, Winter 2004, pp. 14-18

When Republican Jeffrey Pollock ran for Congress in Oregon in 2000, he promoted the use of federally mandated Internet blocking software in public schools and libraries. But after discovering that his campaign Web site was blocked, he joined librarians, civil liberties groups, parents, children, and Web publishers seeking to overturn the Children’s Internet Protection Act (CIPA). That law, recently upheld by the Supreme Court, mandates use of blocking software on public library and school computers as a condition for eligibility to receive e-rate discounts or federal grants under the Library Services and Technology Act (LSTA) and Title II of the Elementary and Secondary Education Act (ESEA).

The Problem with Filters

As candidate Pollock learned, filters may do more harm than good. They sweep too broadly, blocking only some sites with indecent materials while restricting access to thousands of legal and useful resources, and failing to block communications sent through e-mail, chat rooms, non-Web sources, peer-to-peer exchanges, and streaming video—now popular modes for distributing pornography. Filters are cumbersome to disable and to override. They do not reflect library selection criteria, nor do they block the images cited by CIPA as obscene, child pornography, or harmful to minors. They are costly to purchase and maintain.


Filters can give parents and guardians a false sense of security—prompting them to believe that children are protected when they are not. Numerous studies have documented that filters fail to block many sites banned under CIPA. 1 One conducted for the Kaiser Family Foundation found that filters do not block access to one in ten pornography sites under conditions simulating intentional access, and one in three pornography sites under conditions simulating accidental access. 2 Plus young people have little trouble finding these unblocked sites or loading software that bypasses filters altogether. 3 Even if they encounter filters at schools and libraries, children can still gain unfiltered Internet access at home, friends’ houses, or elsewhere. What’s more, filters cannot protect children from other dangers and concerns they might encounter, such as potential predators, gambling, or fraud. These are all issues better addressed through education than by pinning one’s hopes to a simple technological fix.


Filters not only underblock, they also overblock significant amounts of perfectly legal, useful information, such as Web pages for the Quakers, Congressional candidates like Jeffrey Pollock and House Majority leader Dick Armey, Native American sites, safe sex, AIDs prevention, Mother Jones magazine, the National Rifle Association, the Democratic Party, and Beanie Babies. Beyond specific Web pages, filters may also block entire news and commentary sites, such as Salon.com and sites that convert works from English to other languages—sites that filtering companies believe circumvent filtering. Because filters often categorize an entire Web site or IP address based only on a small portion of that site’s content, many individual pages are unnecessarily blocked, nor counted when evaluators assess overblocking rates. The National Research Council (NRC) cites another problem: “Filter vendors have many incentives to err on the side of overblocking and few to err on the side of underblocking.” 4 Even the government’s expert witness in the CIPA case admitted that 6 to 15 percent of the blocked sites that he analyzed “did not contain . . . sexually explicit content.” 5 Ann Lipow, an American Library Association (ALA) witness in the CIPA case and an experienced librarian, determined that almost all of these blocked sites were appropriate for public library users of any age. 6

Reviewing Internet Sites

Filtering company staff cannot begin to review all three billion publicly available Web pages indexed by search engines such as Google, let alone the far larger number of pages of the deep Web—content that resides in searchable, direct-query databases. 7 Nor can they keep up with characterizing more than five million new Web pages added daily with an average life span of forty-four to ninety days. 8 Only about 1.5 percent of Internet sites are considered pornographic; and of those, the best filters block about 75 percent when set at the highest levels. At the same time, filters block at least 20 percent of the three billion benign Web sites—a whopping 600 million-plus sites. When confronted, filtering companies refuse to reveal the 200,000 to 600,000 URLs on their word or site lists, nor the criteria used for blocking them, which they consider proprietary. 9 David Burt of the filtering company N21 defended this decision by declaring, “We aren’t going to release it because we don’t want our competitors to get it.” 10 Yet users need this information to select the filters that best serve their needs. In an editorial following the CIPA decision, Vicky Rideout, vice president of the Kaiser Family Foundation, challenged the filtering companies:

It’s time to bring the process of Internet filtering out in the open. . . . Filtering vendors cite proprietary rights and competitive reasons for protecting details about how and what they block. But this secretiveness needs to be abandoned; a public mandate necessitates a public right to know. 11

How Filters Work

Filtering programs function in a fairly simple way. Control lists work by either word or site blocking. 12 Only limited staff is available to review sites, focusing almost exclusively on those in English and making subjective judgments about sites that only courts can determine are illegal. Blocking categories do not match a library’s selection criteria, nor are they based on the expertise of professional librarians. Decisions about what users may view are relegated to companies with no public accountability. Furthermore, the categories used by filtering systems do not correspond to those that libraries are required to block under CIPA, nor do they restrict access solely to visual depictions that are obscene or child pornography for adults, or harmful to minors for young people under seventeen years old. As a result, no filter is actually CIPA compliant.

Age Considerations

Aside from overblocking and underblocking, filtering systems do not distinguish between a six- and a sixteen-year-old. Too often, filters are set to apply for the youngest users at the expense of all others. While age poses a problem for adjusting settings, it also presents challenges for libraries when determining whether to override erroneously blocked individual Web sites for minors or to disable filters altogether for adults, necessitating procedures that incorporate age eligibility while assuring anonymity for adults who request disabling. 13

Overriding and Disabling

In district court, several expert witnesses testified that it is technologically impossible to unblock only those images that are not obscene, child pornography, or harmful to minors. They pointed out that a block cannot be done on just one terminal or for a predetermined period. In addition, multiple people cannot be vested with unblocking authority, a caution sounded by several blocking companies. Moreover, experts claim that customization of blocking programs requires technical expertise equivalent to a systems administrator—a specialist rarely resident in many small and rural libraries. Not only did these experts find unblocking cumbersome, but also they emphasized that it creates a burden or even a stigma for users uncomfortable with or too busy to request that the library override a block, particularly when the action may take several days to complete. 14 Surprisingly, Supreme Court Justice Anthony Kennedy disregarded this testimony in his concurring judgment in the CIPA case, stating:

If, on the request of an adult user, a librarian will unblock filtered material or disable the Internet software filter without significant delay, there is little to this case. . . . If some libraries do not have the capacity to unblock specific Web sites or to disable the filter or if it is shown that an adult user’s election to view constitutionally protected Internet material is burdened in some other substantial way, that would be the subject for an as-applied challenge, not the facial challenge made in this case. 15

Installation and Maintenance Costs

Filters are expensive to install and maintain, resulting in an unfunded mandate for poor communities. Unfortunately, federal E-rate and LSTA funds will not cover acquisition and maintenance costs—costs that may exceed monies granted by these programs. Libraries are also finding that the unblocking or disabling requirements raised by the Supreme Court may result in the need for additional staffing. But that amount is paltry compared to the expense of defending the lawsuits that still may ensue. Six Supreme Court justices concurred that Congress can require libraries to filter in order to qualify for certain federal grants; but they also opened the door to as-applied challenges should libraries find they cannot readily unblock constitutionally protected sites.

Bridging the Digital Divide

Even though the Internet promises new opportunities for everyone to participate in the information society, research consistently indicates that many low-income, non-English speaking, disabled, elderly, rural, and inner-city groups are falling behind in their ownership of computers and access to telecommunications networks. 16 One institution alone can bridge that divide. Libraries play that special role, not just in providing access, but also in ensuring that the public can find content of interest and apply the necessary skills to utilize information successfully. Programs such as the E-rate and LSTA target low-income communities, assisting public libraries in becoming the number-one point of access for those without computers at home, school, or work. And because the Internet is now the only point of access to “a wide variety of government services, educational materials, health resources, communication tools, and commercial activities,” the role of libraries is even more critical to bridging information access gaps for disadvantaged Americans. 17 Indeed, libraries serve as the sole logon point for 10 percent of Americans. 18 For these, and for others, CIPA threatens that bridge. According to the Partnership for Progress on the Digital Divide,

Requiring filters on library computers undermines that goal by relegating those who rely on libraries to second-class Internet access. As a consequence, CIPA undermines their ability not only to communicate via the increasingly important mechanism of e-mail, but to find needed information about health, jobs, civil rights, politics, and many other topics. 19

Ensuring a Safe and Enriching Online Experience for Children and Adults

At the district court trial that brought the CIPA case to the Supreme Court, librarians from across the country demonstrated the many effective ways that their local libraries ensure a safe and enriching experience online for children and adults alike. These librarians emphasized that filters cannot take the place of preferred routes that include Internet-access policies, user-education programs, links to great sites, safety guidelines, and reference assistance. They also reported that their libraries locate terminals in places that allow for public monitoring while protecting the confidentiality of users’ online experiences. Some also install privacy screens or recess monitors to ensure greater user privacy. Equally important, they described how most public libraries teach users how to use the Internet effectively and efficiently, and link children, teens, and adults to great sites as well as to safety information, such as GetNetWise. 20

The vast majority of citizens use the Internet and other library materials responsibly, guided by local library Internet access policies and codes of conduct that address appropriate use and invoke disciplinary action if rules are violated. Nearly two-thirds of libraries require parental permission before children can use the Internet. Close to half have used filters on some terminals, some successfully employing software that permits users to choose whether or not to invoke a filter. And not surprisingly, less than 20 percent select filters when offered an option, even when it is for their children.

The bottom line is that librarians are dedicated to ensuring free and open access to information so that everyone can participate in our democracy. Every day in every community, we librarians stand in defense of this principle. We ensure that libraries are inclusive, and that no person or idea is excluded. That commitment explains why members of the ALA Council voted overwhelmingly against the use of filtering software that blocks constitutionally protected speech. 21 ALA strongly encourages local libraries to adopt, implement, revise, and enforce Internet use policies that protect public access to information and promote a positive online experience while respecting the right and responsibility of adults to guide their children’s library use. In so doing, librarians can help parents and children make good choices and ensure they are well versed in navigating and evaluating sites on the Internet, thus saving them from drowning in a sea of undigested information online. As the NRC report concluded, “neither technology nor public policy alone can provide a complete—or even a nearly complete—solution. Nor is technology a substitute for education, responsible adult supervision, and ethical Internet use.” 22


The 2003 Supreme Court CIPA decision forces many libraries to choose between their core values of intellectual freedom and equity of access, versus the acceptance of federal funds requiring the installation of faulty technological protection measures. ALA is providing legal, technical, and financial information in order to assist librarians and their communities in making informed decisions and sorting through options. For those libraries that filter, ALA urges them to protect citizen’s First Amendment rights by minimizing the blocking of legal and useful content, encouraging users to report problems, and making filter disabling as obvious and unobtrusive as possible.

The Supreme Court decision also provides libraries with an excellent opportunity to communicate their vital role in providing a safe and enriching online experience, leaving no Americans behind in the information age. With or without the use of filters, the best protection that libraries can employ is a good education and communication program, combined with sound up-to-date policies and safety procedures. Libraries now must review their existing Internet and privacy policies to ensure that they represent recent developments and to communicate their concerns with their communities. Once reviewed, libraries should post these policies prominently, as well as display links to Internet safety tools such as GetNetWise and documents prepared by the National Center for Missing and Exploited Children. By providing a means to alert citizens to their rights and collecting complaints, librarians can renew their efforts to communicate to Congress and other policy makers just how burdensome and discriminatory filtering mandates can be.

Children as well as adults need to learn for themselves the critical viewing and information skills that will lead them to make good judgments about the material that they encounter on the Internet and elsewhere. As concluded by NRC:

Swimming pools pose some threat to the safety and well-being of children. But swimming pools provide benefits to their owners—and children—in many different ways. Technology—in the form of fences around pools, pool alarms, and locks—can help protect children from drowning in swimming pools. However, teaching a child to swim—and when to avoid pools—is a far safer approach than relying on locks, fences, and alarms to prevent him or her from drowning. 23

Both children and adults need to be able to assess as well as access information—to distinguish between that which is useful and that which is not. We do not help when we simply wall them off from information and ideas that are controversial or disturbing. Regrettably, forcing libraries to choose between funding, equitable access, and censorship means millions of library users will lose, particularly those Americans who reside in the most poverty-stricken areas of the country.

References and Notes

1. See, for example: Caroline Richardson and Paul Resnick, “See No Evil: How Internet Filters Affect the Search for Online Health Information” (study conducted for the Kaiser Family Foundation), Journal of the American Medical Association 288, no. 22 (Dec. 11, 2002): 2,887–94. Accessed Sept. 2, 2003, www.kff.org/content/2002/20021210a; Online Policy Group and the Electronic Freedom Foundation, Internet Blocking in Public Schools: A Study on Internet Access in Educational Institutions (San Francisco: Online Policy Group, June 2003). Accessed Sept. 2, 2003, www.eff.org/Censorship/Censorware/net_block_report/net_block_report.pdf; National Research Council, Tools and Strategies for Protecting Kids from Pornography and Their Applicability to Other Inappropriate Internet Content (Washington, D.C.: National Research Council, 2001). Accessed Sept. 2, 2003, U.S. Children’s Online Protection Act Commission, Final Report of the COPA Commission Presented to Congress, Oct. 20, 2000 (Washington, D.C.: Govt. Print. Off., 2000). Accessed Sept. 2, 2003, www.copacommission.org/report; Lori Bowen Ayre, Internet Filtering Options Analysis: An Interim Report. Infopeople Project, May 2001. Accessed Sept. 2, 2003. For additional examples and analyses, see Ben Edelman, Sites Blocked by Internet Filtering Programs: Expert Report for Multnomah County Public Library et al., vs. United States of America et al. (Cambridge, Mass.: Ben Edelman, 2002). Accessed Sept. 2, 2003, http://cyber.law.harvard.edu/people/edelman/mul-v-us; Marjorie Heins and Christina Cho, Internet Filters: A Public Policy Report (New York: Free Expression Policy Project, 2001). Accessed Sept. 2, 2003, www.fepproject.org/policyreports/fiteringreport.html; Christopher D. Hunter, " Filtering the Future?: Software Filters, Porn, PICS, and the Internet Content Conundrum" (master’s thesis, Univ. of Pennsylvania, Annenberg School for Communication, 1999). Accessed Sept. 2, 2003; The Peacefire Censorware Pages. Accessed Sept. 2, 2003, www.peacefire.org/censorware; The Censoreware Project, The Censorware Project Website. Accessed Sept. 2, 2003. The U.S. District Court for Eastern Pennsylvania, American Library Association v. the United States et al. No. 01-1303: Opinion of the Court. (Philadelphia, May 31, 2002). Accessed Sept. 2, 2003, http://news.findlaw.com/nytimes/docs/ala/cipa53102ord.pdf. Also available as Appendix to the Jurisdictional. Statement, appendix A,   68a–89a: Accessed Sept. 2, 2003, www.usdoj.gov/osg/briefs/2002/2pet/7pet/2002-0361.pet.app.pdf.

2. Richardson and Resnick, “See No Evil.”

3. See, for example, Peacefire’s Web site, Instructions for Getting around Blocking Software. Accessed Sept. 2, 2003, www.peacefire.org/circumventor/simple-circumventor-instructions.html. The circumventor program that anonymously circumvents filtering software was developed by the U.S. government’s International Broadcasting Bureau, which broadcasts the Voice of America, in order to defeat filtering in China and other countries that suppress or monitor Internet use of their citizens.

4. National Research Council, Sections 12.1.8 and 12.1.3.

5. U.S. District Court for Eastern Pennsylvania (J.S. Append A), 91a.

6. U.S. District Court for Eastern Pennsylvania (J.S. Append A), 82a.

7. At the district court, Geoffrey Nunberg estimated that the deep Web is two to ten times the size of the indexable Web. U.S. District Court for Eastern Pennsylvania, (J.S. Append A), 30a. Other experts estimate that public information on the deep Web is currently 400 to 550 times larger than the commonly defined Web searched by Google and other navigation tools. See, for example, Michael K. Bergman, “The Deep Web: Surfacing Hidden Value,” The Journal of Electronic Publishing 7, no. 1 (Aug. 2001). Accessed Sept. 2, 2003, www.press.umich.edu/jep/07-01/bergman.html.

Steve Lawrence and C. Lee Giles, “Accessibility of Information on the Web,” Nature 400 (July 8, 1999): 107–9. Note: Lawrence and Giles estimated the average Web page life as forty-four days. Geoffrey Nunberg, in his expert testimony in the CIPA case, estimated that the average Web page life as ninety days.

9. U.S. District Court for Eastern Pennsylvania (J.S. Append A), 49a.

10. Shia Kapos, “Librarians Grapple with How to Filter Computers,” The Associated Press, July 11, 2003. Accessed Sept. 2, 2003.

11. Vicky Rideout, “Internet Filters Block Valuable Data, Too,” USA Today, August 6, 2003, A11.

12. For an easy to understand description of how filters work, see: Karen Schneider, Filtering: No Easy Answers: Plain Facts about Internet Filtering Software (Chicago: ALA/PLA, 2001). Accessed Sept. 2, 2003.

13. U.S. Supreme Court, United States et al. v. American Library Association, Inc., et al., No. 02–361, Syllabus and Opinion of the Court (Rehnquist, p. 1). Accessed Sept. 2, 2003.

14. American Library Association,  CIPA: Legal FAQs. Accessed Sept. 2, 2003.

15. U.S. District Court for Eastern Pennsylvania, (J.S. Append A), 46a–48a; Edelman, Sites Blocked by Internet Filtering Programs, 32–35.

16. U.S. Department of Commerce National Telecommunications and Information Administration, Falling through the Net: A Survey of the "Have Nots" in Rural and Urban America (Washington, D.C.: National Telecommunications and Information Administration, 1995). Accessed Sept. 2, 2003, www.ntia.doc.gov/ntiahome/fallingthru.html; U.S. Department of Commerce, National Telecommunications and Information Administration, Falling through the Net II: New Data on the Digital Divide (Washington, D.C.: National Telecommunications and Information Administration, 1998). Accessed Sept. 2, 2003, www.ntia.doc.gov/ntiahome/net2; U.S. Department of Commerce, National Telecommunications and Information Administration, Falling through the Net: Defining the Digital Divide (Washington, D.C.: National Telecommunications and Information Administration, 1999). Accessed Sept. 2, 2003, www.ntia.doc.gov/ntiahome/fttn99/contents.html; U.S. Department of Commerce, National Telecommunications and Information Administration, Falling through the Net: Toward Digital Inclusion   (Washington, D.C.: National Telecommunications and Information Administration, 2000). Accessed Sept. 2, 2003, www.ntia.doc.gov/ntiahome/fttn00/contents00.html; U.S. Department of Commerce, National Telecommunications and Information Administration, A Nation Online: How Americans Are Expanding Their Use of the Internet (Washington, D.C.: National Telecommunications and Information Administration, 2002). Accessed Sept. 2, 2003, www.ntia.doc.gov/ntiahome/dn/index.html; Amanda Lenhart, The Ever-Shifting Internet Populations: A New Look At Internet Access and the Digital Divide (Washington, D.C.: Pew Internet and American Life Project, 2003). Accessed Sept. 2, 2003.

17. Tammi Moe and Keith Curry Lance, Colorado Public Libraries and the Digital Divide 2002 (Denver: Colorado State Library, Library Research Service, 2002). Accessed Sept. 2, 2003.

18. U.S. District Court for Eastern Pennsylvania (J.S. Append A), 36a–37a.

19. Marjorie Heins on behalf of the Partnership for Progress on the Digital Divide et al., Brief Amici Curiae of Partnership for Progress on the Digital Divide et al., in Support of Appellees United States of America v. American Library Association et al., No 02-361, Supreme Court of the United States (New York: Free Expression Policy Project, 2003). Accessed Sept. 2, 2003, www.fepproject.org/courtbriefs/cipabrief.pdf.

20. Association for Library Services to Children,  Great Web Sites for Kids : Accessed Sept. 2, 2003; GetNetWise, Online Safety Guide (Washington, D.C.: GetNetWise, n.d.). Accessed Sept. 2, 2003, http://kids.getnetwise.org/tools/searchsafe/.

21. See: American Library Association, Resolution on the Use of Filtering Software in Libraries (passed by the ALA Council, July 2, 1997). Accessed Sept. 2, 2003; Resolution on Opposition to Federally Mandated Internet Filtering (passed by the ALA Council, Jan. 17, 2001). Accessed Sept. 2, 2003;  Statement on Library Use of Filtering Software , ALA Intellectual Freedom Committee, July 1, 1997; revised November 17, 2000. Accessed Sept. 2, 2003.

22. National Research Council, Section 14.3.

23. Ibid., Section 10.3.