DOIs and PubMed Central - why no links?
Further to my previous post "NIH Mandate and PMCIDs" we've been looking into linking to articles on publishers' sites from PubMed Central (PMC). There are a couple of ways this happens currently (see details below) but these are complicated and will lead to broken links and more difficulty for PMC and publishers in managing the links. CrossRef is going to be putting together a brieifing note for its members on this soon.
The main issue we are raising with PMC, and that we will encourage publishers to raise too, is why doesn't PMC just automatically link DOIs? Most of the articles in PMC have DOIs so this would require very little effort from PMC and no effort from publishers and would give readers a perisistent link to the publisher's version of an article.
Current PMC linking methods. 1) Links on Author Manuscripts in PMC are pulled in from PubMed's LinkOut service which requires the publisher to register with PubMed and provide linking files. The DOI can be specified as the linking mechanism via LinkOut.
2) For final version of articles in PMC the journal image at the top of the page can be linked to the journal homepage or can have a "this article" link to the publisher's site. The publisher has to sign up with PMC for specifying the header graphic and the links. The PMC instructions (Word document) say "The static base (http://www.biomedcentral.com/) of the URLs for this link comes from the HTML template. PMC then dynamically completes the URL by adding an issn/vol/page. " and then says that any item in the XML (such as the DOI) can be used.
Both of the approaches outlined above require extra work and will be difficult for smaller publishers. In addition, the links will be fragile by not being based on DOIs. Publishers can specify that DOIs can be used but it isn't easy. We'd like to leverage the resources that publishers have already put into the DOI system but automatically making the DOIs active links - it would be very easy.
Comments
Don't forget that in addition to LinkOut built into PubMed, PubMed ALSO supports sending the user to their local institution's link resolver. This is an important third way.
The problem with DOIs that in fact initially motivated the creation of link resolvers is the "appropriate copy problem". Just following the DOI with CrossRef, the user may be taken to a copy of an article they are not licensed to view and may be given a come-on to pay $20 for the article. Meanwhile, there may be another copy of the article their library has ALREADY paid for them to access, but which the DOI does not take them to. But their local library's link resolver does.
Please don't omit this important additional linking method PMC already in fact has. Of course, there are problems to this too, which we could talk about.
Posted by: Jonathan Rochkind | May 14, 2008 5:09 PM
My understanding (which may be incorrect) is that the publisher links in PMC don't support OpenURL linking but I fully take your point that PubMed LinkOut supports this.
The Appropriate Copy issue was recognized early on and DOIs can resolve to link resolvers if users are set up for this - see "OpenURL and CrossRef".
I think activating the DOIs in PMC as links should be done in addition to other linking methods.
Posted by: Ed Pentz | May 15, 2008 6:13 AM