On versioning in RePEc

August 21, 2009

RePEc carries research in various formats. While journal articles are unique (with very few exceptions), working papers, as they are pre-prints, may be duplicates of listed articles, and they may even appear in different versions, either because they are published in different series, or because there may be updates within a series. We believe that is important to carry all versions, not just the last one, for the following reasons.


  1. Time-stamps: A working paper allows to establish when some research was conducted and thus determines preeminence of research ideas. Given publication delays in Economics, this can be important.
  2. Open access: Many journal articles have gated access. Such restrictions can be bypassed by reading working papers, which are mostly open access.
  3. Link to published version: It is still preferred to use published versions in citations, especially once a paper is accepted in a journal. The originally cited working paper is often linked to its published version.
  4. Visibility: Working papers are much more read than journal articles, both because they are more current and they are freely available. In addition, working papers are disseminated through NEP.

The process of linking the various versions of the same work is not obvious, however. With about 800,000 works in RePEc, performing matches on titles is a daunting task, especially as fuzzy matching is necessary due to slight variations in punctuation and spelling. For this reason, we do the matching only across the works listed in an author’s profile. This ensures that the likelihood of two works being different versions of the same one to be very close to 100%. But this also means that such matching cannot be done for works where none of the authors is registered, or where a registered authors did not add all versions to the profile, thereby indicating he/she is not the author of this particular version, rightly of wrongly.

In some cases, titles change across versions, or journal editors require a title change. In such cases, a manual link between versions can be added, just contact a member of the RePEc team with the relevant RePEc handles.

4 Comments | RePEc features | Permalink
Posted by Christian Zimmermann

EconPapers and LogEc on new hardware

August 12, 2009

Thanks to the continued support of the Swedish Business School at Örebro University, EconPapers and LogEc are now running on new and upgraded hardware. This will allow for the smooth running of these services over the next few years as the coverage of RePEc continues to grow and new features are added to the services.

EconPapers is a website that displays all the bibliographic data collected through RePEc. Contents can be browsed in various ways. A powerful search engine is also available. LogEc collects and displays statistics about abstract views and downloads from EconPapers and other participating RePEc services. Both EconPapers and LogEc are run by Sune Karlsson.

1 Comment | Workings of RePEc | Permalink
Posted by Christian Zimmermann

RePEc in July 2009

August 4, 2009

The month of July is generally calm. Regular classes are not in session on campuses, researchers are on vacation or at conferences, thus it is to be expected that RePEc sees little new material or traffic. We counted 674,639 File downloads and 2,287,995 abstract views, relatively modest numbers, saw only six new archives: Universidad de los Andes, Katholieke Universiteit Leuven (II), Spiru Haret University Brasov, Austrian Academy of Sciences, ETH Zürich (III), German Council for Social and Economic Data. The first added Venezuela to our list of participating countries, which is now at 68.

We still managed to pass a few thresholds:

400000 online articles
12500 listed book chapters
5000 subscribers to NEP-HIS, the largest subscriber base in NEP

Leave a Comment » | Workings of RePEc | Permalink
Posted by Christian Zimmermann

Volunteer recognition: Bernardo Batiz-Lazo

July 31, 2009

Bernardo Batiz-Lazo is a business historian with a deep interest in the dissemination of research. Quite naturally he became editor of NEP-HIS and quickly, in 2000, took the responsibility for the whole NEP project until 2007. He is still very much involved, still editing NEP-HIS, which is the mailing list with the most subscribers, at now over 5000. Occasionally, he has also edited other NEP reports on an interim basis.

Under Bernardo’s auspices, NEP grew tremendously. First, he made sure that every field of economics and some fields in business are covered by NEP. In principle now, every new working paper in RePEc should be picked up by at least one NEP report and announced by email and RSS. This required a substantial recruitment effort of new volunteer editors, complicated by the fact that new fields needed to be covered. Bernardo also worked hard to increase the subscriber base, not because it would increase revenue (there is none), but because of the network effects that make it more worthwhile to post papers on RePEc, and thus subscribe to NEP, etc.

While Bernardo retired from NEP leadership duties (taken over by Marco Novarese), he is still very active in the RePEc community, both in internal discussion and with NEP-HIS.

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Posted by Christian Zimmermann

About RePEc impact factors

July 27, 2009

Impact factors have always been a popular way to measure the influence of academic journals. They have been popularized by ISI, now part of Thomson. RePEc also provides impact factors, and this post is about explaining the differences between the two.

ISI takes a sample of journals and analyzes the citations across those journals. To be eligible, a citations has to appear within two years of the publication of the cited article, the cited article must be printed (not forthcoming, a working paper or a manuscript), and the cited article must be among the analyzed journals (286 in Economics). ISI is currently experimenting with a five year window, in addition to the existing two-year window.

RePEc considers all publications listed in its bibliographic database. Thus, it also considers other publication forms than journal articles: close to 1000 journals and 2600 working paper series. It imposes no time window, citations of any age qualify. In most cases, a citation of a working paper will count towards its published form once the article is included in RePEc, possibly after the original citation (condition: at least one author has both versions in his/her RePEc profile). This implies that working paper series and book series can also have impact factors. RePEc is thus more comprehensive.

However, the pool of citations RePEc is drawing from is different. It relies very much on working papers (who can later be published), as they are typically openly accessible. Some publishers also provide references in the bibliographic metadata, but not all. One implication of this is that RePEc is more current as it includes citations to and from research that is not yet published. As research gets published, this data gets updated. But as references from many journals are missing, RePEc citation data must still be treated as experimental. Whether these omissions matter remain to be seen. After all, impact factors always have to be considered in relative terms, not in absolute terms, and if omissions were not biased, they would not matter.

Another major difference is that RePEc excludes self-citations. This is an important issue as some journals, explicitly or implicitly, encourage authors to cite other articles published within the two year window in the same journal. Thus, just as self-citations are excluded for authors, they are excluded for journals. And this can matter a lot.

Finally, the impact factor is determined by divided the eligible citations by the number of eligible articles. ISI determines itself what articles are eligible for the denominator, and this can even be negotiated with the publisher. In RePEc’s case, if an article (or a working paper) is listed, it counts without adjustment.

RePEc also publishes variations on the “simple” impact factor: recursive impact factors, where every citation counts with the impact factor of the citing publication, this favors impact over numbers; discounted impact factors, where the impact of a citation decays with time (regardless of the age of the cited item; and a combination of the two, discounted recursive impact factors. Finally, there is now also the h-index. All variations have a different story to tell about the publication, and RePEc offers the reader the choice.

Leave a Comment » | Bibliographic features in RePEc, RePEc rankings | Permalink
Posted by Christian Zimmermann

Moving time is time to update RePEc data

July 19, 2009

Summer is when most academics move to new affiliations or responsibilities. It is thus a good time to detail what needs to be done for RePEc data to remain accurate. There are close to 30’000 contact details listed in RePEc, yet only 466 have expired email addresses. You can help keeping this list short.

Registered authors

If your email address changes, log in at the RePEc Author Service with your old address, then click on “Contact details” to amend your email address and any other contact details. Note: do not create a new account with your new email address. This would create a duplicate, and then links to and from your profile would disappear once the old account is deleted. Remember also to amend your affiliation(s) if necessary.

Note that starting next month, authors with obsolete email addresses will not count towards their affiliation’s ranking. This is under the assumption that if the email address is not valid anymore, it must be because they have moved.

RePEc archive and series maintainers

If your email address is changing, or if there is a new person in charge, amend your series and/or archive templates. These are the *seri.rdf and *arch.rdf files in the root of your archive. There is no need to email us, as we extract from your templates the addresses for the monthly emails. However, if your RePEc archive moves to a new location, we obviously need to know about it.

Editors

Editor data is provided at two locations: by the RePEc Author Service and by the relevant publishers. In the first case, an email address change is handled as for a registered author. If you are not an editor anymore (and your editorship is listed in your RePEc profile), you can remove this by logging in at the RePEc Author Service: click on “Research” then “identified”, check your old journal, and approve the removal. To add a journal you now edit to your RePEc profile, either look at the suggested research items (if your publisher put in your name in the RePEc data), or do a manual search with the journal title.

Your publisher may also provide directly your name and your email address to RePEc. Your can see this on the listing of your journal on EconPapers or IDEAS. There you see also a technical contact. This is where you need to email to request a change in the listing.

Leave a Comment » | Use of RePEc data | Permalink
Posted by Christian Zimmermann

RePEc in June 2009

July 10, 2009

What’s up at RePEc? We are happy to see an ever increasing popularity of our services, which has manifested itself last month with a record number of newly participating archives, 26, or one every working day: Univesidad de San Andres, Universität Marburg (II), Intervention, University of Florence (II), Bucharest University of Economics (III), University of Warsaw, Lucian Blaga University, University of Queensland (II), Universidade Federal de Goias, Banque de France, National Bank of Poland, Griffith University, University of Malaya, Associazione Rossi Doria, Superintendencia de Valores y Seguros, Basque Institute of Competitiveness, Bancaria, Jerusalem Institute for Market Studies, University of Buckingham Press, Sacred Heart University, Cahiers d’Économie Politique, Universidad Nacional de La Plata, University of California Riverside, Osaka University, Asociación Española de Historia Económica, Red Iberoamericana de Economía Ecológica.

In terms of traffice, we counted 725,569 file downloads and 2,588,500 abstract views. This allowed us to break the mark of 40 million downloads since we started counting this. As usual, many details are available at LogEc.

In terms of thresholds, we are proud to announce the following for June 2009:

60,000,000 article abstract views
40,000,000 downloads
15,000,000 article downloads
650,000 items available online
450,000 listed journal articles
250,000 book chapter downloads
10,000 listed book chapters
10,000 online book chapters

Leave a Comment » | Workings of RePEc | Permalink
Posted by Christian Zimmermann

RePEc coverage outside of academia

June 29, 2009

RePEc indexes research in Economics, and one usually thinks about publications in journals and pre-prints disseminated by universities through the form of working papers or discussion papers. The fact is that a lot of research is also conducted outside these institutions. Take as an example central banks. Beyond their role of managing the money supply in their respective countries, as well as in some cases operating the payment system and regulating parts of the financial system, they conduct research to facilitate their operations and more generally understand the economy.

Much of this research is also present on RePEc. The following central bank have opened RePEc archives: Australia, Austria, Belgium, Brazil, Canada, Chile, Colombia, Cyprus, Czech Republic, England, France, Greece, Hong Kong, Hungary, Iceland, Ireland, Italy, Japan, Latvia, Lithuania, Luxembourg, Mexico, Netherlands, New Zealand, Norway, Peru, Poland, Spain, Turkey, United States (all Federal Reserve Banks). The following participate through an aggregator: Finland, Germany, Sweden, Switzerland. And finally, the following supranational institutions have a RePEc archive: Bank for International Settlements, European Central Bank, International Monetary Fund. There are plenty of other governmental institutions participating as well, in particular statistical offices, ministries and regulators.

Leave a Comment » | Dissemination of research in Economics | Permalink
Posted by Christian Zimmermann

The best top level institutions in Economics

June 21, 2009

RePEc rankings are surprisingly popular, despite their experimental status, in fact this is the most read topic on this blog. So to cater to the interest of our users, let us add another ranking… RePEc has been ranking institutions for quite a while now, using the institutions listed in EDIRC. This ranks, say, at the department level, not at the university level. This is detrimental to institutions where economists are scattered in various departments, in particular in departments that are not listed in EDIRC, for example law, political sciences and statistics. A new ranking is now computed that assembles all authors within the top level institution for their affiliation(s), say a university, a government, etc. Current results are here.

The methodology is the following. For affiliations listed in EDIRC, the top level is used. That would typically be a university. For affiliations not listed in EDIRC, the homepage domain of the institution submitted by the author is matched with any institutions listed in EDIRC. If no match is found, it is taken as is. Finally, as usual with multiple affiliations, a weighing scheme is used to distribute the author’s score across all affiliations.

Note a few particularities. All components of the University of London (LSE, Imperial College, etc.) are all merged into one. All subdivisions of a national government are also merged. US Federal Reserve Banks, however, are not merged, as they are top level in their respective states.

6 Comments | RePEc rankings | Permalink
Posted by Christian Zimmermann

RePEc on Facebook

June 13, 2009

Following a comment made in the suggestion box, a Facebook group has been created. Apart from the usual function of such groups, users can discuss a proposed application that would allow to include some information from RePEc in their Facebook profile. If you are both a RePEc and a Facebook user, you are welcome to join.

3 Comments | Use of RePEc data | Permalink
Posted by Christian Zimmermann

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