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Copyright ©2000-2003
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Why Filters Can't Work

In December 2000, the United States Congress passed legislation mandating Internet filtering software use to block pornographic materials in all public schools and libraries funded through federal programs.

The problem is:


Here are ten good reasons why:

  1. Underblocking
    No filtering software is clever enough to block even 10% of the pornography on the Internet unless it effectively blocks most or all of the materials on the Internet. This is because of the inherent complexity of human language and thought, not a matter of simply improving filtering technology.

  2. Overblocking
    Filtering software always blocks more material than the small proportion of pornography it is able to block, thus significantly damaging the most basic and practical uses of the Internet, not to mention the free speech rights and civil liberties of every person accessing, publishing, or broadcasting on the Internet. Most of the material on the Internet is informative and useful and should not inadvertently or intentionally get blocked.

  3. "Expert" Control
    Even the simplest filtering software is difficult to operate in a way that permits local control over the specific type and scope of materials blocked, so people who have to use filtering software depend on "experts" in filtering software companies who decide what they should and should not see, then keep this information secret even from those using the filtering software. (Only one filtering software company makes the list of blocked sites available to customers or the general public.)

  4. Subjective
    Criteria used to block materials are vaguely defined and subjectively applied to everyone who accesses the Internet, rather than designed and customized to meet the needs of particular communities.

  5. Error-Prone
    Filtering software companies make lots of mistakes in assigning sites to block lists and almost always rely on automated systems for making content decisions. The process is fraught with error and there is usually no effective means to check whether a site is blocked inappropriately, to correct the problem, to override the blocking, or to appeal the multitude of incorrect decisions made by filtering software companies.

  6. Censorship
    When the U.S. government mandates filtering in public schools and libraries, the government mandates censorship in direct conflict with the U.S. Constitutional guarantees to free expression and freedom of association. Laws prohibiting the production and distribution of child pornography and obscenity already apply to the Internet.

  7. Discrimination
    Filtering software blocks "controversial" materials related to certain issues or communities disproportionately more than other materials, thus unfairly discrimination against whole communities of people accessing, publishing, or broadcasting on the Internet.

  8. Vulnerable
    Filtering software blocking can be relatively easily bypassed even by children.

  9. Problematic
    Use of filtering software causes problems with computers during installation, maintenance, upgrades, and removal that negatively impacts the use and performance of the computers, including computer crashes, access time delays, web display errors, and other problems impacting negatively the ability to access the Internet effectively.

  10. Wrong Focus
    Internet filtering software is an unsuccessful panacea to an important problem that requires a more thoughtful solution. Parents, teachers, librarians, administrators, and local communities must work together to come up with Constitutionally acceptable solutions that encourage learning in a safe environment on the Internet, rather than relying on an unworkable technological fix. The focus should be on determining local standards and on education for all parties about how to use the Internet effectively.

Additional Resources

OPG logo
Online Access: Filtering Software
Resources on filtering software and related issues, Online Policy Group

Statement on Library Use of Filtering Software
Filtering resources such as explanation of what filters are and problems associated them, American Library Association Intellectual Freedom Committee, November 17, 2000

CPSR logo
Filtering FAQ
Frequently-asked questions about filtering, including a consideration of problems with filtering technology, Computer Professionals for Social Responsibility, October 24, 1998

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