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Dead references

Science is built on the work on others. This means researching numbers, methods, and principles from previous articles, all which must be correctly referenced. Without referencing, you risk making claims which cannot be substantiated, or worse, being accused of plagiarism.

Academic course submissions are routinely run through analysis software to detect unreferenced material. The rules of plagiarism are drilled into every modern student, made even more important due to the ease of access of online content, or cheating using paid essay-mills.

I am currently working on a meta-analysis paper which means I have had to read lots of academic articles. It’s normal to flick back and forth between the main text and a specific reference. This is like falling into a Wikipedia browsing hole, but instead your browser tabs are filled with PDFs and journal articles to come back to.

A few of these papers go back to 2007, which is a long time in computing history. But even with papers that have been published this year, I have encountered a major problem: dead references.

This is a solved problem in academic publishing. The Digital Object Identifier (DOI) is used across more than 5,000 publishers whereby every published item is assigned a unique, permanent identifier. A DOI is like a URL in that it points to a specific piece of content, but unlike a URL it is guaranteed to always point to the authoritative source. Indeed, a DOI redirects the user to that source — it doesn’t host any content itself — but means that even if the publisher rearchitects their systems, the DOI can be updated to always point to the correct location. There are now over 190 million unique items referenced since the system went live in 2000.

“Publication” used to mean a permanent version made available with any changes or corrections issued as a separate article, or edition. This is true for academic publications and books, but does not work like this for the rest of the internet. Websites regularly change. Reports are taken down. Domains expire. It has been suggested that the average lifespan of a webpage ranges from 44, 75 or 100 days. Ironically, one of the sources referenced in that article has itself been taken offline.

This internet impermanence is recognised in referencing guidelines. The Harvard referencing system, for example, requires non-DOI publications to include an “accessed” date. This at least sets a reference time for when the material was viewed. But what are readers supposed to do with that information?

How do we address this? #

Firstly, I suggest that authors use the “save it” option of the Internet Archive Wayback Machine to capture a copy of the referenced page. Over 451 billion web pages have been saved in this way, and they are regularly crawled after being saved for the first time. In the article itself the display URL in the references can show the original URL, but the href location could point to the Wayback Machine version. This would allow readers to go to the current version but quickly reference the dated version if necessary.

Secondly, I suggest that academic journals require authors to supply a copy of all reference material alongside the submitted article. I hope that the Internet Archive remains available forever, but they have faced repeated legal attacks around copyright to the material they publishYou can help support them in many ways, but we can’t rely on a single copy of reference material. Instead, this could at least be stored by the article publisher, if not released as part of the supplementary material that often accompanies papers.

Copyright regulations do not help this situation. The challenge with storing (and potentially republishing) reference material is the licensing. Academic publications are traditionally available only through subscription journals. Open access is gaining popularity, and I aim to publish all my academic writing under open access licenses, but this is not yet common practice. It is also expensive. I was able to use the Imperial College London Open Access Fund, otherwise I would have had to pay around £1,000 as a processing charge (payable after acceptance, not like low-quality pay-for-publication journals).

That said, I would argue the principle of fair-use applies to re-publishing reference material and journals should do this as standard.

What I am going to do #

In the absence of any action from publishers, authors can save to the Wayback Machine even if their references do not link to it. This makes a copy ready for someone else to access in the future.

For every article I write, I am going to take a copy of the material for every reference and then upload it to a GitHub repository for that paper (to be made public once any embargo period ends). The repository will contain the published version of the article and a copy of every reference. The repository will be archived to make it read only, I will upload a copy of it to my Internet Archive account, and trigger a save as part of the Software Heritage Archive.

For WordPress users, you can automate this. I run the LH Wayback Machine plugin which automatically submits all WordPress content to the Internet Archive when content changes.

Keeping a copy of everything important is a necessary step in the ephemeral world of the internet. That doesn’t mean hoarding data (like e-mail) but it doesn’t take much to consider what might be relevant reference material in the future.

For more on this topic, have a listen to this episode of the a16z podcast with the founder of the Internet Archive.