A 2001 survey conducted by the Henry J. Kaiser Family Foundation found that 70% of 15-17-year-olds say that they have used the Internet to look up health information, with almost 40% of adolescents having searched for information on a sexual health topic such as pregnancy, birth control, or sexually transmitted infections. Most of these teens are trying to access this information at home, school, or the library—places where blocking software is often used to limit minors’ exposure to pornography and other controversial materials. Though many have suggested that this blocking software is also filtering out legitimate websites that address issues of health and sexuality, very little evidence exists regarding blocking errors.

A recent study detailed in the December 11, 2002 issue of the Journal of the American Medical Association (JAMA) tried to tackle this question by testing 6 different blocking software packages commonly used in schools and libraries, as well 1 product commonly used on home computers. They discovered that the level of blocking (least restrictive, moderately restrictive, most restrictive) had much more influence on how many legitimate health websites were blocked than how much pornographic material was allowed through. When using the most restrictive setting, health information blocking increased substantially (24%), while the added benefit in blocking pornography was barely perceptible.

About the Study

Researchers from the University of Michigan set out to quantify the extent to which pornography-blocking software used in schools and libraries limits access to health information websites. After observing 12 teens conducting a total of 69 health information searches, a computer model was developed that simulated information-seeking by adolescents. To obtain a sample of websites for the analysis, researchers first determined six frequently used search terms in each of the following five categories:

  • Health topics unrelated to sex (eg, diabetes)
  • Health topics involving sexual body parts, but not sex related (eg, breast cancer)
  • Health topics related to sex (eg, pregnancy prevention)
  • Controversial health topics (eg, abortion)
  • Pornography

They then took these 30 “search strings” and ran them in each of the 6 most common Internet search engines for teens: Yahoo, Google, America Online (AOL), Microsoft Network, Ask Jeeves, and Alta Vista. The researchers then coded the resulting 3987 unique web addresses according to whether or not they contained health information or pornographic content. Sites that contained both health information and pornography were classified as pornography for all analyses.

The researchers defined 3 settings for each blocking product. The least restrictive settings were designed to block only pornography. The moderate settings blocked pornography as well as a few other categories such as illicit drugs, nudity, and weapons. And the most restrictive configuration for each product blocked all topics or categories that would conceivably be blocked in schools or libraries (everything except news, health, education, finance, search engine, and job search sites).

Researchers determined the percentage of health and pornography sites that were filtered out by each blocking product at each blocking level. They looked at blocking products as a whole, as well as, compared to the each other.

The Findings

Of the 3987 sites that were identified, 2467 contained health information and not pornography, 516 contained pornography, and 1004 were rated as neither health information nor pornography. As the level of blocking increased from least to most restrictive, the frequency of health sites blocking increased substantially compared to relatively little increase in pornographic site blocking. The average blocking rates of all the products were as follows:

  • Least restrictive blocking settings: health sites (1.4%), pornography (87.2%)
  • Moderate blocking settings: health sites (5.2%), pornography (89.8%)
  • Most restrictive blocking settings: health sites (24%), pornography (91.1%)

At the least restrictive setting, 5% of all health sites were blocked by at least 1 product. This compares with 16% of sites for moderate blocking settings and 63% of sites for the most restrictive settings.

The researchers also ran their blocking test on 586 top health information sites that are recommended for teens. They found that the least restrictive setting blocked an average of 0.5% of health information sites. This compares with 2.5% at the moderate settings and 23% at the most restrictive settings. Though there were some differences between products, the blocking settings, rather than the blocking products, had the most influence over the number of health information websites that were blocked.

Though these results are compelling, there are some limitations to this study. First, it is possible that the search terms the researchers used did not accurately reflect what teens might use during an actual search. A computer model based upon the activities of 12 teens may not have captured the searching practices of teens in general, nor does it detail how search progress might be influenced when encountering blocked sites. Second, there was no attempt to rate the quality of the health information or the relevance of health sites to the search topics. There was also no attempt to check whether alternative sources of the same health information were available for blocked sites. Finally, it is not clear whether the different blocking software products could accurately be compared because they varied widely in the parameters used to determine low versus high restrictive settings.

How Does This Affect You?

This study suggests that using pornography-blocking software at the lower restrictive settings are just as effective at blocking pornography—while still allowing access to important health information. Individuals and institutions using these blocking technologies may want to consider using these lower settings to assure access to potentially important health care information. Other possibilities for improving access and streamlining health searches is to bookmark high quality health sites for when teens are searching for this type of information on the Internet.