Linkrot made headlines last month as a malady infecting half of the high Court’s citations to uniform resource locators (URLs)—“In Supreme Court Opinions, Web Links to Nowhere” reads the headline in the New York Times Sidebar.
And in another, Wall Street Journal blogger Jacob Gershman reports, “Supreme Court Says It’s Resigned to ‘Linkrot.’” While a Supreme Court spokeswoman quoted in the blog post confirms that the Court archives its cited web sources in the case files, lack of access to a disappeared Internet source relied upon in an opinion is problematic. There is always the Internet Archive’s Wayback Machine, but its intermittent captures do not include every page on the Internet and cannot reliably retrieve the cited source.
According to a recent study, some law journal citations are just as blighted by rot. This post looks at the study and describes a just-launched service to remedy rotten links in law journal citations. But first, let’s get our rot lingo right.
Linkrot and reference rot defined
The term linkrot personally conjures up images of stem rot or fruit drop induced by plant pathogens, and for good reason. Linkrot is when the URL that is the link between the citation and the cited source no longer works. It is not to be confused with the closely related reference rot, where the cited link works but the content on the page has changed. In either case, the desired fruit can no longer be found at the end of the vine.
The rot problem
Over the years there have been a few studies on the extent of linkrot in Supreme Court decisions, law journals, and legal and policy materials, as well as in medical, computer science, and library science scholarship. The study that triggered the headlines described above was reported in a working paper posted to the Social Science Research Network by Harvard law and computer science professor Jonathan Zittrain and law student Kendra Albert. The authors distinguish their study from the others as one that deploys a methodology designed to ferret out reference rot in working links.
Zittrain and Albert investigated linkrot and reference rot in three Harvard law journals and in all U.S. Supreme Court decisions (a total of 555 URLs since 1996, when the first hyperlink was cited). In “spot-checking” those URLS that linked to a working page, the authors found that over 70% of the URLs in the law journal citations and 50% of the URLs cited in U.S. Supreme Court decisions “do not link to the originally cited information.”
The study also critiques efforts and suggestions aimed at solving the problem, including WebCite, a permanent linking and archiving service that is presently threatening to close unless donations are forthcoming; the digital object identifier system (DOI), which would require participation by the content creators; and the Internet Archive, where coverage is hit or miss and where storage and ownership are centered in a single organization. The authors then discuss a new permanent linking and archiving service that operates across a distributed network of libraries—Perma.cc.
The Perma.cc solution
Perma.cc is a webpage archiving system developed by the Harvard Law School Library and the Harvard Innovation Lab. Founding members of the project include CloudFlare, Inc., the Digital Public Library of America, the Internet Archive, and 26 academic law libraries in the United States and England. The service allows authors or editors to create a permanent, unalterable cache of Internet content being cited in a legal or scholarly work that is then retrievable by a Perma.cc link assigned to the cache.
According to the Terms of Service, the user must have the rights needed to both direct that the content be archived and to grant Perma whatever rights it needs to provide the service in relation to the content. The user also warrants that archiving the content does not violate the copyrights or rights of others. The content cached must be freely available on the Internet (cannot be paid-only or login-only content) and must be “cited in a legal or scholarly work.” Content is submitted at the user’s risk.
The guide Permanent Links for Law Review Citations: Perma, DOI, and Handle, prepared by the Boston College Law Library, describes the target links for archiving as ephemeral websites like blogs and working papers and other content that does not already have a stable URL. Screens shots of content viewed online, like pop-ups or ads that are temporally experienced, are other possible candidates for archiving when cited in a scholarly work. Content that may be difficult to archive using Perma.cc is discussed in the guide.
The service is still being beta tested and, from what I can tell, implemented at some law schools. Although it is not yet open to the public, Perma is considering requests for beta access on the home page. When the service is up and running, it will be free.
How Perma.cc works
The way this will work is that an author writing a scholarly article pastes the URL of the cited Internet source into the box on the Perma home page. Perma downloads the content at the URL and creates a new Perma.cc link. This potentially creates an immediate record of the cited content at the moment the author types the citation into a work, preventing reference rot from the get go. For the Perma links and caches to be permanent, however, they need to be vested. That’s where you, the law journals, come in.
Journals can open a vesting account by asking a participating library to sponsor it. The library can sponsor a journal if it is “a scholarly journal of the sort that a library would subscribe to and archive.” The role of the vesting members (or journal staff) is to verify that the Perma.cc link in fact points to the cited material and that it is being cited in a scholarly work, warranting its being vested. Journals with vesting accounts may also create Perma.cc links for citations to URLs when an author has not provided them.
Vested links and content are forever in Perma.cc and will not be deleted or taken down unless legally ordered. Unvested Perma.cc links that an author creates are preserved for two years with the option to renew. Once a link is vested, what makes the cache permanent is a distributed network of libraries around the country that stores and preserves copies of the data in the event that it is compromised at one location.
What an archived page looks like
This is a Perma.cc link [http://perma.cc/0WNvsHVwhT5] to Zittrain’s blog post on The Future of the Internet and How to Stop It. The metadata on the page indicates that the cache was created on October 2, 2013, at 1:40 p.m. From here, you have several viewing options. You can view the cache (1) as a live web site as it presently exists (the default view), (2) as an archived site (no new content since the link was created can be viewed but links from the page cached are active), (3) as a screen capture of the page (no clickable links), or (4) as extracted text containing only the main body of the archived page and none of the page’s sidebars, footers, and other features.
Access to analytics
Perma tracks the number of views of a Perma.cc-linked cache and displays the statistic at the top of the page. By creating a new link to that now-archived content, the question arises whether the web analytics will be available to the creator of the archived page. On Zittrain’s Perma.cc-linked page cited above, the default view is to the live site. In fiddling with a Perma.cc link to my own blog, accessing the blog from the Perma.cc link appeared to register views in WordPress.com’s statistics. Also, Perma recommends citing the source URL with the Perma.cc link following in brackets, which could still generate clicks to the original site.
Other possible uses
Perma is focusing the service on citations in legal scholarship for the time being, but as Zittrain told the New York Times, “there is no reason . . . why it could not also work for the Supreme Court.” Another possible use of Perma.cc links is in the open repository of U.S. case law being developed by the Free Law Project at the UC Berkeley School of Information.
Although vesting accounts are intended for “scholarly journals and similar entities,” professor blogs may be likely candidates for vesting accounts as well, to the extent that they cite to ephemeral sources. It would also be a great tool for noncommercial scholarly journal publishers in other fields, were the capacity there.
Kudos to the creators and partners
This is a much-needed, cheap (free!), and easy-to-use tool for authors and law journals to capture, preserve, and permanently link to Internet sources cited in footnotes, before they disappear. Kudos to the law libraries, legal experts, researchers, and innovators involved!
 Adam Liptak, “In Supreme Court Opinions, Web Links to Nowhere,” Sidebar, New York Times, September 23, 2103, http://www.nytimes.com/2013/09/24/us/politics/in-supreme-court-opinions-clicks-that-lead-nowhere.html?_r=1&.
 Jacob Gershman, “Supreme Court Says It’s Resigned to ‘Linkrot,’ ” Law Blog, Wall Street Journal, September 26, 2013, http://blogs.wsj.com/law/2013/09/26/supreme-court-says-its-resigned-to-linkrot/.
 Nicholas Tomaiuolo, “DOIs, URLs, LoCKSS, and Missing Links,” Searcher (July/August 2006): 22.
 Jonathan Zittrain and Kendra Albert, “Perma: Scoping and Addressing the Problem of Link and Reference Rot in Legal Citations” (Social Science Research Network, working paper series, September 21, 2013): 1, http://ssrn.com/abstract=2329161.
 Ibid., 2–4.
 Tomaiuolo, “Missing Links,” 19–20.
 Zittrain and Albert, “Perma,” 4.
 The journals that were the subject of the study are the Harvard Law Review, Harvard Law School Human Rights Journal, and the Harvard Journal of Law and Technology, beginning with volumes in 1999, 1997, and 1996, respectively (ibid., 1–2, 5).
 Ibid., 7–8.
 Ibid., 2, 6, 8.
 Ibid., 9–10.
 Ibid., 10–11.
 Ian Chant, “Perma.cc Aims to Bring Staying Power to Online Legal Citations,” Library Journal October 2, 2013, http://lj.libraryjournal.com/2013/10/academic-libraries/perma-cc-aims-to-bring-staying-power-to-online-legal-citations/.
 “About Perma,” Perma.cc.
 Ibid., ¶ 5(a)(iii) & (c).
 Ibid., ¶ 5(a)(iv).
 Ibid., ¶ 5(a)(i).
 Ibid., ¶¶ 5(b), 8, 10(c).
 Boston College Law Library, Permanent Links for Law Review Citations: Perma, DOI, and Handle (October 1, 2013): 1, http://lgdata.s3-website-us-east-1.amazonaws.com/docs/302/893343/Using_Perma.pdf.
 Zittrain and Albert, “Perma,” 11.
 Boston College Law Library, Permanent Links, 2–3.
 “Perma Terms,” ¶ 10(c).
 “About Perma,” Perma.cc.
 “About Perma,” Perma.cc; “General/User FAQs,” Perma.cc.
 “General/User FAQs,” Perma.cc.
 “About Perma,” Perma.cc.
 Chant, “Staying Power.”
 Ed Summers, “On perma.cc,” Inkdroid (blog), September 26, 2013, http://inkdroid.org/journal/2013/09/26/on-perma-cc/.
 “Vesting Member FAQs,” Perma.cc.
 Liptak, “Web Links to Nowhere.”
 Chant, “Staying Power.”
 “General/User FAQs,” Perma.cc.