On the Web
Evaluating Web-Based Information: Access and Accuracy John Markwell Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, NE 68588 David W. Brooks* Department of Teaching, Learning, and Teacher Education, University of Nebraska–Lincoln, Lincoln, NE 68588; *
[email protected] Several years ago we began developing a series of Web-based chemistry courses for high school teachers drawing on what then was an emerging array of excellent teaching materials being developed by educators and scientists around the world. Our plan was to develop testing materials using extant Web materials as much as possible, rather than creating new materials for each topic. Thus, the courses we developed contained numerous hyperlinks (1). The Lives and Half-Lives of Web Sites on the World Wide Web Early on we observed that links were breaking, and we made reports on the “link rot” phenomenon (2–4). The observation that Web-based resources were ephemeral was first systematically studied starting in 1996 by Koehler (5) in the context of library science. Koehler’s report suggested that the lifetime of 361 random Web pages was approximately two years. Subsequently, studies of larger numbers of URLs within the context of library science (6) and law (7) agree that “dead” Web sites are a significant problem. The problem of link rot affects not just education; it has been found to be causing a significant erosion of available supplementary information for published scientific research in journals such as Nature, New England Journal of Medicine, Lancet, and Proceedings of the National Academy of Sciences (8).
URLs Remaining Active
600
500
400
300
200
100
Table 1. Distribution of Nonviable Biochemistry URLs by Domain World Wide Web Domain
0 0
10
20
30
40
50
60
70
80
Duration / month Figure 1. Viability of the original 515 URLs charted as a function of time. The first-order equation N = 519 × exp(‒0.013 × months) was used to generate the dashed line.
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We have now studied the links in our Web courses for more than one half-life; starting with 515 working biochemistry-related links in August 2000, 244 links were functional 60 months later (Figure 1) and only 181 still active after 78 months. This is longer than the 2–3 years estimated for URLs in law review articles (7), yet similar to the 4–5 year half-life estimated for a collection of 2729 URLs, including 985 from the sciences (6). No single top-level domain was immune from the loss. Over a 70-month period, the most common domains lost an average of 63% of the total (515) URLs, as shown in Table 1. These results are similar to the observations of Tyler and McNeil (6), except that they found the .gov top-level domain to be one of the more stable. For reasons that are not clear, the observed URL loss displayed in Figure 1 closely correlates to a first-order decay with a half-life of about 55 months. This may be evidence for cyberentropy, but we will leave such research to younger colleagues with longer anticipated lifetimes. Part of this loss can be understood in terms of the nature of the times. When the project started, numerous courseware software packages were competing in the academic marketplace. As more support systems for courses became formalized, the informational materials began moving behind firewalls, thereby making them accessible only to enrolled students. Another part of this loss results from normal Web updating, and so forth. As faculty change teaching assignments and support hardware and software evolve, little attention is paid to maintaining access— perhaps because there is little incentive to do so. Some of the Web sites had surprising developments. Our course originally linked to several sites illustrating the potential impact of steroid consumption on human strength. It was revealed later that some of these sites were connected with illicit sales; site developers asked both that links be removed and any copies destroyed to prevent extending their periods of incarceration. There were also two of our sites that suddenly became advertisements for pornography.
Lost Viability over 70 Months, %
.com (commercial)
68.0
.edu (educational)
65.0
.gov (government)
86.0
.org (organization)
47.0
Average of all domains
63.0
Journal of Chemical Education • Vol. 85 No. 3 March 2008 • www.JCE.DivCHED.org • © Division of Chemical Education
On the Web
In marked contrast with this Journal—which provides electronic versions of all the articles from all the past issues (1924 to present) to subscribers’ computer desktops—we see a different attitude prevailing toward preservation of materials online. In addition to the frustration of encountering nonfunctioning links, using Web links as valid citations in the primary scientific literature has the potential to cause future problems in analysis of the supporting evidence for scientific discoveries (8). Accuracy of Web-Based Material An innovative concept emerging from the WWW is that of decentralized authoring and editing to massive knowledge bases. A wiki is Web software that permits easy addition, removal, and editing of content, “sometimes without the need for registration” (9). Some have contended that this is the start of an era of emerging collective knowledge. An advantage of a wiki is that, oftentimes, anyone can add or edit an entry. While this probably increases the likelihood that knowledgeable persons will become involved in creating and editing items, it also makes the information suspect. Stephen Colbert of the television program, The Colbert Report, has openly attempted to manipulate data by urging viewers to participate (10). On the other hand, the ability to edit Web materials very rapidly appears to be an important advantage of Web-based information. At one time this Journal had a series entitled “Textbook Errors”. Recently, Lower, an author known for very high quality work, posted revised and expanded general chemistry materials (11) on the Web. Shortly after making this content available online, a few minor errors were pointed out and the inaccurate material was corrected and reposted within minutes. The veracity of Web content, however, is clouded by misinformation. A study reported in Nature (12) addressed this topic. For the study, experts were asked to evaluate entries in Wikipedia1 and Brittanica;2 of the 42 entries reviewed, experts found eight “serious” errors, four from each source. Also noted were “factual errors, omissions, or misleading statements”: 162 ascribed to Wikipedia and 123 attributed to Britannica. The initial assertions made in the Nature article have generated responses and rebuttals (13). The public access approach to resource generation presents risks in terms of accuracy, motives, uncertain expertise, volatility, and heavy reliance on Web-based resources (14, 15). Chemistry teachers are now researching, teaching, and learning in a new era in which access to scientific information is faster and simpler while less reliable than in the past as supported by the data we present. In spite of intensive efforts and professional editing, there always have been errors in “published” materials. Although current evidence (13) suggests otherwise, the veracity of information appears to be growing more suspect. At present, the collaborative Wikipedia project does seem to be a useful starting point for research by sufficiently skeptical undergraduate students (16). However, it appears that we must
help these students understand the difference between initial inquiry and scholarship. Literature Cited 1. Pedagogical Content Courses for High School Chemistry Teachers. http://dwb4.unl.edu/Chem/ChemPed.html (accessed Dec 2007). 2. Markwell, J.; Brooks, D. W.; Langell, M. A.; Emry, R.; Crippen, K. J.; Brooks, H. B.; Abuloum, A.; Cohen, K. C. J. Chem. Educ. 2007, 84, 1861–1865 3. Markwell, J.; Brooks, D. W. J. Sci. Educ. Technology 2002, 11, 105–108. 4. Markwell, J.; Brooks, D. W. Biochem. Mol. Biol. Educ. 2003, 31, 69–72. 5. Koehler, W. J. Am. Info. Sci. 1999, 50, 162–180. 6. Tyler, D. C.; McNeil, M. portal: Libraries and the Academy 2003, 3 (4), 615–632. 7. Rumsey, M. Law Libr. J. 2002, 94, 27–39. 8. Evangelou, E.; Trikalinos, T. A.; Ioannidis, J. P. A. FASEB J. 2005, 19, 1943–1944. 9. Definition of “Wiki” at Wikipedia. http://en.wikipedia.org/wiki/ Wiki (accessed Dec 2007). 10. The Colbert Report. http://en.wikipedia.org/wiki/The_Colbert_ Report (accessed Dec 2007). 11. Lower, S. Chem 1 Virtual Textbook: A Reference Text for General Chemistry. http://www.chem1.com/acad/webtext/pre/ (accessed Dec 2007). 12. Giles, J. Nature 2005, 438, 900–901. 13. Giles, J. Internet Encyclopaedias Go Head to Head. http://www. nature.com/nature/journal/v438/n7070/full/438900a.html (accessed Dec 2007). 14. Denning, P.; Horning, J.; Parnas, D.; Weinstein, L. Comm. ACM 2005, 48 (12), 152. 15. Read, B. Chron. Higher Educ. 2006, 53, 31–36. 16. Lipcznska, S. Research Reviews 2005, 19, 6–7.
Notes 1. Wikipedia is a multilingual, Web-based, free content encyclopedia project collaboratively written by more than 75,000 active contributors whose entries are subject to ongoing review and revision. Wikipedia Home Page. http://wikipedia.org/ (accessed Dec 2007). 2. Encyclopædia Britannica began as a traditionally published, printed (fixed) resource, now also available online to subscribers, with some content accessible without subscription. Encyclopædia Britannica Online Home Page. http://www.britannica.com/ (accessed Dec 2007).
Supporting JCE Online Material
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