An academic library recently reached out to us regarding literature on the severity of link-rot. Having these in one place can be useful for anyone looking into it, though – find a collection of these below!

  • The study that inspired’s creation: this study of law journals from ’99 to 2011 found more than 70% of the URLs do not link to the originally cited information, as well as 50% of the URLs in US Supreme Court opinions.
  •  In a study from the Hiberlink team of 3.5 million articles from 1997 to 2012, they found that in 2012 alone 22% of Elsevier article hyperlinks had rotted, with the percentage higher for each previous year,
    • 4/5ths of all 2012 papers contained at least one link that suffered reference rot, i.e., at least one reference to web content was either dead or not archived until some time after the publishing date.
    • 75% of all links in the study were not cached on an archiving site within two weeks of the article’s publication date, meaning the content might not reflect the citing author’s original intent.
  • A more recent study by the same group found that of the links examined, for those that still worked, 75% of them led to content that was different from what was originally referenced.
  • A study from Nanyang Technological University covering 7 years of science journals specifically showed 31% of links rotted, with .edu links at the highest rate: 36%.

At a library and wondering how best to let those there know how they can use Perma to fight link-rot? Many libraries set up a simple LibGuide with a contact email for those who want to utilize at their institution, such UMass’ here (archive) or Virginia Tech’s here (archive).

Perma now offers individual user subscriptions, organizational accounts, and free accounts for those at academic institutions. Perma was made at and is supported by the Harvard Law library, part of the oldest library system in the United States, and supported by a network of libraries. Use it to make a short-link to a preserved copy of the webpage you’re citing to – a link you can trust won’t die or go away. Nearly 1,000,000 citations saved!