Comments on: What’s the average lifespan of a Web page? http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/ Preservation of Web Resources: a JISC-sponsored project Tue, 16 Mar 2010 16:32:23 +0000 http://wordpress.org/?v=wordpress-mu-1.2.5 By: Avi Rappoport http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-33659 Avi Rappoport Wed, 03 Mar 2010 20:20:14 +0000 http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-33659 I found the source: http://www.sciam.com/0397issue/0379kahle.html Kahle, Brewster, Preserving the Internet, Scientific American, March 1997 I found the source:

http://www.sciam.com/0397issue/0379kahle.html

Kahle, Brewster, Preserving the Internet, Scientific American, March 1997

]]> By: Web Page Life Span « The ADL Librarian http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18712 Web Page Life Span « The ADL Librarian Tue, 18 Aug 2009 00:39:46 +0000 http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18712 [...] this context, I came across, a posting, “What’s the average lifespan of a Web page?“. It was nice to read a sort of scientific discussion of this nuisance. The posting pulls [...] […] this context, I came across, a posting, “What’s the average lifespan of a Web page?“. It was nice to read a sort of scientific discussion of this nuisance. The posting pulls […]

]]> By: ResourceShelf » Blog Archive » What’s the average lifespan of a Web page? http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18452 ResourceShelf » Blog Archive » What’s the average lifespan of a Web page? Wed, 12 Aug 2009 21:45:42 +0000 http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18452 [...] Marieke Guy does an impressive job pulling together several estimates and the underlying papers where they come from. It’s one challenging question and getting even more so each day in this time of Twitter and similar services. [...] […] Marieke Guy does an impressive job pulling together several estimates and the underlying papers where they come from. It’s one challenging question and getting even more so each day in this time of Twitter and similar services. […]

]]> By: Michael Day http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18442 Michael Day Wed, 12 Aug 2009 16:24:52 +0000 http://jiscpowr.jiscinvolve.org/2009/08/12/whats-the-average-lifespan-of-a-web-page/#comment-18442 As the quotation from my <em>Collecting and preserving the World Wide Web</em> report implies, Alexa's 75 day estimate was also referred to in a 2001 scientific paper written by Lawrence <em>et al</em>. [1]. Ironically, given that paper's subject matter, the only reference provided there was to Alexa's main Web page. From that, I couldn't trace the original percentage (or the methodology used to generate it), so I just used the figure as a general indication of volatility. That said, as you imply, these types of figures can hide a great deal of complexity, in that certain types of Web content are likely to be more stable than others. Moreover, in practice, it probably only makes sense to think about link decay within particular contexts. For example, the article by Lawrence <em>et al</em>. cited above was specifically concerned with Web references in scientific publications, with a case study based on computer science journal and conference papers and technical reports. Their study found that the percentage of invalid links varied over time, e.g. from 23% in 1999 to 53% in 1994. Even then, much of the content (around 80%) was actually still available, and could be found using search engines or other methods. Over the past few years, similar studies have been made of link decay in medical and general science journals [2], followed by similar analysis of various other domains. The evidence here also tends to suggest that link volatility is higher than that of the content itself [3]. Looking that these kinds of detailed studies might actually be more helpful than providing general link decay figures that appear to mean very little. I'm NOT saying that Web link volatility isn't a problem, just that it is difficult to understand what link decay percentages mean without an understanding of exactly what they were trying to measure. <strong>References:</strong> [1] Steve Lawrence, David M. Pennock, Gary William Flake, Robert Krovetz, Frans M. Coetzee, Eric Glover, Finn Arup Nielsen, Andries Kruger, and C. Lee Giles, "Persistence of Web References in Scientific Research," <em>Computer</em> 34(2), February 2001, DOI: 26-3110.1109/2.901164 [2] Robert P. Dellavalle, Eric J. Hester, Lauren F. Heilig, Amanda L. Drake, Jeff W. Kuntzman, Marla Graber, and Lisa M. Schilling, "Going, Going, Gone: Lost Internet References," <em>Science</em>, 302(5646), 787-788, 31 October 2003, DOI: 10.1126/science.1088234 [3] Jonathan D. Wren, "URL Decay in MEDLINE - a 4-year Follow-up Study," <em>Bioinformatics</em>, 24(11), 1381-85, 1 June 2008, DOI: 10.1093/bioinformatics/btn127 As the quotation from my Collecting and preserving the World Wide Web report implies, Alexa’s 75 day estimate was also referred to in a 2001 scientific paper written by Lawrence et al. [1]. Ironically, given that paper’s subject matter, the only reference provided there was to Alexa’s main Web page. From that, I couldn’t trace the original percentage (or the methodology used to generate it), so I just used the figure as a general indication of volatility.

That said, as you imply, these types of figures can hide a great deal of complexity, in that certain types of Web content are likely to be more stable than others. Moreover, in practice, it probably only makes sense to think about link decay within particular contexts. For example, the article by Lawrence et al. cited above was specifically concerned with Web references in scientific publications, with a case study based on computer science journal and conference papers and technical reports. Their study found that the percentage of invalid links varied over time, e.g. from 23% in 1999 to 53% in 1994. Even then, much of the content (around 80%) was actually still available, and could be found using search engines or other methods.

Over the past few years, similar studies have been made of link decay in medical and general science journals [2], followed by similar analysis of various other domains. The evidence here also tends to suggest that link volatility is higher than that of the content itself [3]. Looking that these kinds of detailed studies might actually be more helpful than providing general link decay figures that appear to mean very little. I’m NOT saying that Web link volatility isn’t a problem, just that it is difficult to understand what link decay percentages mean without an understanding of exactly what they were trying to measure.

References:

[1] Steve Lawrence, David M. Pennock, Gary William Flake, Robert Krovetz, Frans M. Coetzee, Eric Glover, Finn Arup Nielsen, Andries Kruger, and C. Lee Giles, “Persistence of Web References in Scientific Research,” Computer 34(2), February 2001, DOI: 26-3110.1109/2.901164

[2] Robert P. Dellavalle, Eric J. Hester, Lauren F. Heilig, Amanda L. Drake, Jeff W. Kuntzman, Marla Graber, and Lisa M. Schilling, “Going, Going, Gone: Lost Internet References,” Science, 302(5646), 787-788, 31 October 2003, DOI: 10.1126/science.1088234

[3] Jonathan D. Wren, “URL Decay in MEDLINE - a 4-year Follow-up Study,” Bioinformatics, 24(11), 1381-85, 1 June 2008, DOI: 10.1093/bioinformatics/btn127

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