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Cooking Up a Solution to Link Rot

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This post is cross posted on the blog of the Law Library of Congress, In Custodia Legis, which is an excellent source of information on current legal trends and materials from the Library’s collections pertaining to the law. It is a guest post by the Law Library’s managing editor, Charlotte Stichter. When Charlotte is not at her day job she loves to cook, and is currently on a quest to find the perfect recipe for clafouti.

Vivian Jarrell's canned goods, produced from her garden, including tomato juice, pickles, grape juice, and beans. (Photo by Terry Eiler, 1997) (Source: Coal River Folklife Collection, American Folklife Center, Library of Congress,
Vivian Jarrell’s canned goods, produced from her garden, including tomato juice, pickles, grape juice, and beans. (Photo by Terry Eiler, 1997) (Source: Coal River Folklife Collection, American Folklife Center, Library of Congress, )

For those with vivid imaginations, the terms “link rot” and “reference rot” might conjure images of moldy fruit in the back of the office refrigerator or a pungent bag of something unidentifiable pulled from under a car seat weeks after its “use by” date. But the food analogy can only go so far. What the terms are really referring to is the all-too-common problem of hyperlinked web addresses — in legal and academic writing or on web pages, for example — that fail to lead the reader to the consumable content desired, either because the link is rotten (not working at all) or because the particular item sought from the Web’s vast menu has been modified or changed.

The problem stems from the Web’s impermanence, the effects of which have been documented by a number of researchers: Websites can be redesigned or shut down, content can be moved, or service can be restricted without advance notice, making the Web a fluid environment ideal for the fermentation of creative ideas, but also uniquely susceptible to decay. The ubiquitous “404 – File Not Found” error message, among other error messages, alerts the user to link rot. Reference rot can be more difficult to spot, as it concerns modifications to the original ingredients, but might be indicated by a “last modified” message at the bottom of a web page, if noted at all.

During a 2014 internal quality assurance review of recent foreign, comparative, and international law reports prepared by the Law Library’s Global Legal Research Directorate and available on, we found that a significant number of linked references in our reports no longer work. The results of our “taste test” were not surprising: studies by other legal entities have found that more than half of linked webpages in law journal and court opinion footnotes don’t work as intended, which is especially problematic in the legal world, where research documentation and reliable access to historic precedents are paramount. A study that appeared in the Harvard Law Review Forum last year found, for example, that about 66-73 percent of web addresses in the footnotes of three Harvard law journals and nearly 50 percent of web addresses in U.S. Supreme Court decisions from 1996 to 2012 suffered from reference rot. Link rot figures were close behind, and both problems were found to increase dramatically over time.

Our dyspepsia-inducing discovery led us to consider archiving solutions that would allow readers to access linked content in real time, while eating . . . er, reading, without having to jump out of the report to search a database of archived material. This quest ultimately led to a solution known as, which was developed for the legal community by the Harvard Library Innovation Lab. A plan for implementing in the Law Library’s Global Legal Research Directorate is now being cooked up, with a target implementation date of October 1 this year — the beginning of the new fiscal year. This means that hyperlinked footnote references in new reports by the Directorate will also contain a link to an archived version of the referenced web page, allowing readers permanent access to key legal materials. Bon appétit!

Comments (2)

  1. Over the past three years, the Mellon-funded Hiberlink project – a collaboration between the University of Edinburgh and the Los Alamos National Laboratory – has studied reference rot in scholarly communication. It actually tossed the term reference rot to refer to the combination of link rot and content drift. The project has quantified the extent of reference rot at an unprecedented scale (see but it has also proposed solutions. Pro-actively creating an archival copy (Memento) of a referenced resource, as described in the blog post, is indeed an essential component of a solution. But another component is equally crucial: referencing in a robust manner. Referencing the Memento is the intuitive thing to do. But since web archives don’t have a guarantee of eternal life either, and/or because web archives frequently get blocked in certain parts of the world, a link to a Memento may end up rotten itself. That’s why robust references include the original URI, the datetime of linking, and the URL of the Memento. The combination of these information elements, when provided in a machine-actionable manner, provides the ability to deliver robust links that will work long into the future. More about Robust Links at and .

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