Chart by Mary Bakija; see sources below
It may seem obvious that physical media like books and magazines deteriorate over time, but digital media can deteriorate as well. Digital information storage devices like flash drives and CD-ROMs tend to deteriorate or become obsolete much faster than we would expect. But digital media preservation can be tricky not only because of changing technology, but also due to inconsistencies and hiccups online as well.
Have you ever tried to click a link that you saved previously only to find that it doesn't work? Reference rot (or link rot) is a phenomenon that occurs when a URL no longer points to the information that it originally did. This can happen for a number of reasons, including a reorganization of the website, new domain name, or simply being deleted altogether. In fact, the problem is so pervasive — it's estimated that one in five reference links are broken (Klein et al., 2014) — that we may soon find ourselves in a "digital dark age" (Wernick, 2018). There are a number of ways to avoid being stuck without this access, but the easiest two are:
Just a reminder that Zotero does both of these things automatically, saving you some extra steps!
The Wayback Machine
If the content you need has truly disappeared from the internet, and you don't have any saved copy to use, there is a chance you may be able to access it through the Wayback Machine. The Wayback Machine is a project run by the Internet Archive, a non-profit organization that aims to archive the web.The Wayback Machine captures versions of webpages, and allows you to click through a timeline to view various iterations. Certain webpages, such as the website for the White House, are captured more than others. Still, it is always worth checking to see if they have captured the version of a website that you need — it might even be preferable to use a link to the Wayback version of your link reference, as that may be more stable.
Screenshot of Wayback Machine search for whitehouse.gov, captured December 1, 2019
Sources for chart at top:
Erickson, C. L. & Lunt, B. M. (n.d.). Alternatives for long-term storage of digital information. Brigham Young University.
Taylor, N. (2011). The average lifespan of a webpage. Library of Congress.
Gilbert, M. W. (2003). Digital media life expectancy and care. University of Massachusetts.
Henry, A. (2015). How long will my hard drives really last? Lifehacker.
Klein, M. et al. (2014). Scholarly context not found: One in five articles suffers from reference rot. PLOS ONE.
Wernick, A. (2018). Scientists warn we may be creating a 'digital dark age." Science Friday.
To keep your work safe, the Library of Congress recommends you follow the 3-2-1 Rule, which says:
Image by Mary Bakija
Because the program you're using today (like Microsoft Word) might be different — or gone! — tomorrow, saving files in proprietary formats means you might not be able to access it in the future. To guard against that possibility, save your files in a format that is non-proprietary and the most likely to be accessible for the longest period of time.
The Library of Congress provides extensive information about recommended file formats for long-term preservation, but here are a few quick tips:
Of course, sometimes that's not manageable — a TIF file, for instance, will be much larger than a JPG, which may be a burden on your storage capabilities. Also, if possible, saving original files in more than one format can help ensure you're able to open at least one of them in the future.
For more information about what file formats are recommended for different types of digital media, see these resources:
This video will cover a few different ways that you can recover your work if it accidentally gets deleted.
Video by Miranda Siler