Supplementary Open Access

January 23, 2008

Most economic publications do not provide open access. Yet the articles published there may be accompanied with related Internet material that is openly accessible—in particular pre-print, post-print and other versions of the published articles, and including additional material that is unavailable in the published versions. I refer to this as “supplementary open access.”

It is obviously in every author’s best interest to make their works freely available on the Internet, and it is in the interest of all economists to enjoy unhampered access to as many economic research papers as possible. It is also helpful to have open access to other versions of articles in case the original article is not available, too expensive or shortened. This makes it advisable for authors to provide supplementary open access to their published work, in particular access to pre-print versions and post-print versions. (“Pre-print” refers here pre-refereed and “post-print” to post-refereed versions of a published paper).

Supplementary open access has several advantage for authors:

Visibility and citations. In his article “Online or Invisible,” Steve Lawrence has analyzed the effect of online availability of published journal articles in physics on citation. He concludes:

“The results are dramatic. There is a clear correlation between the number of times an article is cited, and the probability that the article is online. More highly cited articles, and more recent articles, are significantly more likely to be online. … When considering articles within each year, and averaging across all years from 1990 to 2000, we find that online articles are cited 4.5 times more often than offline articles. “

There is no reason to assume that economics would be any different, although I do not know a comparable systematic study. My own experience is, though, that those articles I placed online attracted much more attention than comparable articles not available online. The further spreading of Internet publishing since 2000, also witnessed by the growth of the RePEc database, may have further strengthend the effect.

Prestige. Theodore Bergstrom and Rosemarie Lavaty have looked at all articles that appeared 33 economic journals in August 2006 and determined for all papers whether or not an open access version was available on the net. The result:

“… freely available versions of about 90 percent of the articles in the top fifteen listed journals can be found by Google-searching the title and author. […] the self-archiving norm is less strong among those who publish in the less influential journals. Freely available versions of about 50 percent of the articles in the eighteen lower-ranked journals in our sample could be found on the internet.”

Several top-ranked journals (among them QJE, JPE, and Econometrica) scored 100% free accessibility, while lesser journals scored significantly less. The prestige of the journal thus correlates strongly and positively with supplementary open access.

Career concerns. Many hiring decisions are influenced by citation scores. I have mentioned above that open access improves citations and citation scores. These are usually taken from Thompson (Web of Science). The RePEc citation scores are increasingly used for these purposes as well. They refer not only to published work, but also to pre-prints and all other material available through the RePEc services.

For these reasons, authors should be interested in providing supplementary open access to their works. At the same time they help others.

Now to the publishers. Most publishers make supplementary open access easy, but a few still try to restrict public access, in spite of calling themselves “publishers.” (It would be better to call them “concealers.”) You may want to submit only to those publishers that permit some form of supplementary open access. These publishers are “green,” “blue,” and “yellow”:

Green publishers (most publishers) permit you to archive pre-print and post-print versions of your article.

Blue publishers permit you to archive post-print (i.e. final draft post-refereeing) versions of your article.

Yellow publishers permit you to archive archive pre-print (i.e. pre-refereeing) versions of your article.

All these publishers are fine, as far as supplementary open access is concerned. The publishers that are neither green, blue or yellow are “white”:

White publishers (a few) do not support archiving.

As supplementary open access is blocked only by the white publishers, don’t submit to the corresponding journals if possible–and don’t help them with referee reports. They obstruct the dissemination of knowledge.

You find further details on individual journals at the RoMEO database. The publishers’ websites usually offer additional information.

In order to realize the advantages of supplementary open access it does not suffice, though, to shun white publishers. You need also to make your paper available on the Internet. The usual way is to deposit your pre-refereed manuscript at the working paper series of your institution.

Make sure that all information is supplied to the RePEc database. This will guarantee inclusion in the CitEc citation compilations done by RePEc. At the same time, the paper will become easily available through the RePEc services such as IDEAS or EconPapers, as well as Google Scholar and OAIster. In addition, the paper will be advertised through the NEP mailing lists that target specific subjects. All this will make the paper very easy to find.

If your institution’s working paper series does not supply its data to RePEc, you may suggest that they do. (instructions). Otherwise you may consider depositing your paper with MPRA which provides this service. You can also have it both ways: If your institution’s series is not covered by RePEc, you may publish it in addition in MPRA, but this makes sense only if your institutions series is not covered by RePEc. Otherwise please don’t do it, as it creates confusion.

Once your paper is published, leave your pre-print on the repository—do not remove it. If you remove the open access (pre-print or post-print) versions, you lose all citations to these works, which reduces your citation score. Further you prohibit access to readers who have no subscription for the publisher’s data banks. In short, you lose all the advantages mentioned above.

Some further observations. Yes, it is true, readers can buy articles at the publishers’ data banks (such as IngentaConnect, ScienceDirect, or Blackwell Synergy), or at British Library Direct even without subscription, but prices are excessive: You may be easily required to pay 30$ for a book review of just a few pages! Most readers won’t buy a pig in a poke, though. Open supplementary access versions of the original articles help the reader to gather an impression about whether it is worthwhile to have a closer look at the original article. Publishers may increasingly become aware that supplementary open access effectively helps them to sell stuff through their data banks. Hopefully they pass some of the earnings to the authors.

Let me add a quite important additional benefit of supplementary open access: Authors keep the copyright for all material they put on the Internet. If they do not pre-publish, they may lose all rights for their own works! (The current German legislation will transfer all electronic rights to the publishers, for example, unless the author explicitly states by the end of the current year that he or she wants to keep the rights. German university libraries are very worried.) You avoid all these problems to some extent by pre-publishing on the Internet, as all pre-published versions will remain yours, even if the rights for the published version go to the publisher.

A further point: Keep the electronic manuscript of your final version. Green publishers allow you to deposit the final version, but, as a rule, not the publisher’s final PDF. This restriction, if it applies, may be inconvenient, but it does not pertain to the substance of your work. Given this state of affairs it is advisable that you produce your own PDF right after correcting the galleys (by using the free software PDFCreator or the pricey Adobe Acrobat). So you have a version that you can safely use to enhance the impact of your work by providing supplementary open access. But if this seems too cumbersome to you, just leave the pre-print version on the net! The RePEc listings will show these along with the final versions, so that readers are informed about which versions exist, and which one is the latest.

RePEc Author Service is down

January 18, 2008

The RePEc Author Service is down at the time of this writing. IT personel from the College of Liberal Arts and Sciences at the University of Connecticut is currently looking into the issue.

Update (Friday 18:00 EST): The service is back up, after an interruption of about 18 hours. It should be fully functional. Please do not hesitate to report any issues. We are sorry for the inconvenience.

Update 2 (Saturday 7:00 EST): The server went down again, and will not be back up before Monday.

Update 3 (Monday 19:00 EST): The server is still down. When it is back up, we will keep it offline to investigate the problem.

Update 4 (Thursday 18:00 EST): The machine is running (for the moment…) but we are still keeping it offline to work on it.

Update 5 (Tuesday 10:00 EST): All tests have been passed successfully, we are progessively reestablishing all services.

Update 6 (Tuesday 14:00 EST): Everything is looking good so far, expect the service to be available tomorrow if tests continue to look positive.

Update 7 (Wednesday 14:00 EST): The RePec Author Service is back online. Please report anything unusual. It is to be expected that some data is out of date, in particular citation data. Sorry for the inconvenience, and let us hope everything works fine now that the service is live.

The citation extraction process in CitEc

January 16, 2008

CitEc is an experimental autonomous citation index, that is, it is a software system which is able to automatically extract references out of the full texts of documents and create links between citing references and cited papers.

With its last update, the CitEc database has reached almost three million references and more than one million citations between documents available in RePEc. This is an important threshold but still is far of being a complete set of citations. There are some limits in the references extracion process:

First, the system needs to have open access to a electronic version of the documents full text. Many journals listed in RePEc have restricted access and therefore are excluded of CitEc unless they grant special access or push the citations to RePEc in other ways. We are working with some publishers that kindly provide us with metadata about references. We try to get on board as many publishers as possible but unfortunately not all of them are willing to collaborate with us at this time. As a result, the data set is still made up mainly of references extracted from working papers. This has the advantage of provide the most updated data about citations since working papers contains the most recent research results.

Second, the URL provided by the RePEc archive maintainer must be correct and must point to the PDF file containing the document full text and not to an intermediate abstract page or similar. Some archives provides this kind of links to force the researchers to pass through their institutional web pages. The system is unable to follow the links to the hidden papers and they are missed in the references extraction process.

The third limit is more technical. In order to extract references, the PDFs files need to be converted into plain ASCII text. This step is key to successfully complete the process, since a good quality text representation of the document makes easier the identification of references. There are a wide variety of PDF files created in different ways and not all of them can be converted.

Finally, the systems does a parsing of the references section, which first needs to be isolated, to identify each reference and split it in its parts: title, author, year, etc. The parsing is done using pattern matching techniques which in some cases are not able to identify the full list of existing references.

As the las update as of December 31, 2007, the CitEc numbers are: 527,357 articles and working papers available in RePEc. Of them, 343,441 cannot be processed by the system due to limitations mentioned in the first two points above, namely:

101,886 have not an electronic representation

216,110 have restricted access

19,174 have not a direct link to the docuent full text

6,271 have wrong url

That leaves an amount of 183,916 documents available to be processed by CitEc. Of them, the process was successfully completed in 134,130 papers, that is the 73% of the available documents. The complete list of sources and the number of processed documents for each series or journal is available here.

All the previous considerations should be taken into account when CitEc data is used for scientific evaluation purposes. We still consider the data to be experimental.

From the point of view of RePEc archive maintainers there are a few basic steps they can take to improve the situation. For example:

  • provide direct and correct URLs to the documents full text
  • make use of the X-File-Ref to give the system an ASCII version of the references section of a particular document
  • help us to lobby the publishers and editors of the restricted journals asking them to send us metadata about references.

75% of the top 1000 economists are now registered with RePEc

January 8, 2008

The RePEc Author Service recently surpassed 15,000 registered authors, and the post relating this mentions the high coverage among top ranked economists. To document this, take one popular ranking, the one by Tom Coupé that is based on publications from 1990 to 2000. Tom Coupé has two rankings, one where publications are weighted by the impact factors of the journals, the other where citations are counted. According to the “publications” ranking, 75% of the 1000 economists are now registered with RePEc, according to the other 65%. The difference comes from the fact that the latter also includes non-economists (political scientists, statisticians, demographers, law scholars, and sociologists) that are cited in Economics journals.

One particularly interesting aspect of these rankings is how the proportions of registered authors decline with rankings:

Ranks registered,
publication ranking
citation ranking
1-100 93 77
101-200 81 72
201-300 78 69
301-400 73 76
401-500 77 66
501-600 71 61
601-700 73 54
701-800 77 55
801-900 62 62
901-1000 65 60
Total 750 652

How can we explain this pattern? Are registered authors more likely to publish well or be cited? This may be true for more recent measures of visibility, but in 1990-2000, the RePEc Author Service was not yet functional. Are then better ranked authors more likely to care more about their visibility and thus more likely to register?

RePEc in December 2007, and what we have done over Year 2007

January 2, 2008

Every month, a short summary of what happened with RePEc is sent to the RePEc-announce mailing list. I will also put that message, slightly adapted, on this blog.

The major event this month is that we passed to three important thresholds: 15,000 authors, 80% of the material now online, and 1/8 billion abstract views. For some hints at what 15,000 authors represent in the Economics profession, see elsewhere on the blog. Also, we have now released rankings for the most cited recent papers and articles.

As year 2007 is now over, we can reflect on what RePEc has achieved over that year. 158 archives were added, and the total of currently 844 archives have added 108,000 bibliographic items to RePEc, a 24% growth, with 240 new working paper series and 130 new journals. 105,000 new items are online, a 31% growth. 3,500 authors registered, almost ten a day, a 30% growth. Citation analysis coverage increased by 39%.

In 2007, we added also a few new features:

  • Compilations by institutions of all publications from affiliated and registered authors (find institutions on EDIRC)
  • Customized publication compilations: by defining a list of authors or by creating a reading list
  • Registered authors can now manage citations at the RePEc Author Service: delete erroneous ones and approve citations that were deemed dubious matches.
  • Rankings have been improved with more criteria, with rankings within fields and with citation rankings for recent items only.
  • The RePEc blog was inaugurated.

Finally, RePEc celebrated its 10th year in its current form. I think this was an impressive year, and I am looking forward to an even better year 2008!

In terms of traffic, December is expectedly calmer, but we still managed record numbers for the month: 1,822,061 abstract views and 504,315 downloads. This leads us to the thresholds we have passed this month:

125,000,000 cumulative abstract views
275,000 online articles
130,000 items with references
15,000 registered authors
1,900 working paper series
80% of all items available online