…Link and Reference Rot in Legal Citations

Perma: Scoping and Addressing the Problem of Link and Reference Rot in Legal Citations by Jonathan Zittrain, Kendra Albert, Lawrence Lessig.


We document a serious problem of reference rot: more than 70% of the URLs within the Harvard Law Review and other journals, and 50% of the URLs found within U.S. Supreme Court opinions do not link to the originally cited information.

Given that, we propose a solution for authors and editors of new scholarship that involves libraries undertaking the distributed, long-term preservation of link contents.

Imagine trying to use a phone book where 70% of the addresses were wrong.

Or you are looking for your property deed and learn that only 50% of the references are correct.

Do those sound like acceptable situations?

Considering the Harvard Law Review and the U.S. Supreme Court put a good deal of effort into correct citations, the fate of the rest of the web must be far worse.

The about page for Perma reports:

Any author can go to the Perma.cc website and input a URL. Perma.cc downloads the material at that URL and gives back a new URL (a “Perma.cc link”) that can then be inserted in a paper.

After the paper has been submitted to a journal, the journal staff checks that the provided Perma.cc link actually represents the cited material. If it does, the staff “vests” the link and it is forever preserved. Links that are not “vested” will be preserved for two years, at which point the author will have the option to renew the link for another two years.

Readers who encounter Perma.cc links can click on them like ordinary URLs. This takes them to the Perma.cc site where they are presented with a page that has links both to the original web source (along with some information, including the date of the Perma.cc link’s creation) and to the archived version stored by Perma.cc.

I would caution that “forever” is a very long time.

What happens to the binding between an identifier and a URL when URLs are replaced by another network protocol?

After all the change over the history of the Internet, you don’t believe the current protocols will last “forever” Yes?

A more robust solution would divorce identifiers/citations from any particular network protocol, whether you think it will last forever or not.

That separation of identifier from network protocol preserves the possibility of an online database such as Perma.cc but also databases that have local caches of the citations and associated content, databases that point to multiple locations for associated content, and databases that support currently unknown protocols to access content associated with an identifier.

Just as a database of citations from Codex Justinianus could point to the latest printed Latin text, online versions or future versions.

Citations can become permanent identifiers if they don’t rely on a particular network addressing systems.

One Response to “…Link and Reference Rot in Legal Citations”

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