|Too often, educators’ online links lead to nowhere.|
It’s one of those annoyances about the Web that make some teachers wonder why they bother.
After spending hours during the summer searching online for material to enhance their courses, then bookmarking the hyperlinks on their computers or including them on class Web sites, teachers later find that many of the sites no longer work. “It’s very frustrating—when you find a great activity, a Web quest, or research, and you go to the Web site and it’s down,” says Kelly Luton, who teaches Spanish at Robinson Secondary School in Fairfax County, Virginia. And often, a site’s unresponsiveness isn’t temporary. Every day, education-related Web pages pointed to by millions of hyperlinks are erased by their owners or moved to a different online address, leaving only confusing “Not Found 404" or “DNS error” messages—Internet-speak for “no one’s home.”
“Link rot,” as the phenomenon is called, has turned the Web into the world’s biggest piece of Swiss cheese: appetizing, but full of holes. That’s the conclusion of two University of Nebraska professors, John Markwell and David Brooks, who recently published a paper on the problem in the Journal of Science Education and Technology.
Starting in August 2000, the two professors collaborated to create a Web “textbook” for three graduate-level chemistry courses for high school teachers. “My original vision was that there are thousands of sites put up by people who are teaching courses and putting their materials online, and if you could interact with all this material, it would be the equivalent of a textbook,” says Markwell. The academics carefully monitored the 515 links they originally compiled; to their disappointment, the collection eroded steadily. After 27 months, one-third of the links were extinct.
Some of the Web pages Markwell and Brooks had linked to were created by professors who overhauled their sites and established new Internet addresses as their lesson lineups changed. Other times, education companies, scientific groups, and government agencies reorganized their sites and renamed files without providing a link to alert visitors. One Web address was even purchased by a pornographer. “We had a site on how to make yogurt with different bacteria; all of a sudden, they weren’t making yogurt anymore,” Markwell quips.
Given the disappearing act pulled by so many sites, what’s a teacher to do? Educators say bookmarking wisely can save trouble down the road. Luton recommends that teachers “never point to somebody’s personal hobby site, a student site, or one hosted on a free Web provider like GeoCities,” because “they come and go very quickly.” Markwell and Brooks note that in their study, the attrition rate for Web pages with ".com” and ".edu” domain names were significantly higher than for those in the ".org” and ".gov” domains, which are from nonprofit and government-related hosts.
Once links are chosen, they simply must be checked on a regular basis. Markwell, for example, spends about three hours a month replacing dead links with other resources in his three Web textbooks. Hyperlink-checking programs, often called content-management software, can help speed up the process.
Markwell and Brooks are calling for professional societies and government and education organizations to start pooling resources in highly stable public digital libraries. One such effort is the National Science Teachers Association’s new archive of science- related content for educators, organized by grade level and scientific topic. Available online, the Web guides will be carefully maintained and gradually expanded, says Tyson Brown, the program’s manager. High-tech pioneer Brewster Kahle is also attempting to archive the Web at his Internet Archive, a vast and growing historical library of sites dating back to 1996, as well as other cultural artifacts in digital form. Teachers can use its free search engine, called the Wayback Machine, to retrieve Web resources that even their creators believe have been clicked into link-rot oblivion.
For now, though, Markwell says his research has dimmed his hopes for widespread use of Web textbooks—at least ones created by teachers. “If I were teaching in a K-12 setting,” he says, “I’d be more likely to use a commercial site that provides stable material that has walls around it.”