RePEc rankings: adjustments and novelties

March 26, 2010

Given the increased interest in the various RePEc rankings, as well as thanks to comments made by users, I have made various adjustments over the last months. Some are barely perceptible, while some give some new features. Here is a short list.


Aggregate ranking for series and journals
Thanks to popular demand, there is now a ranking that aggregates the four impact factors, the h-index, download counts and abstract views. This ranking is available for journals, working paper series and all series.
Linked series
By linked series, I mean the situation where a series ceased to exist and continues under a new name. This happens in particular for journals that switch publishers, or journals that merge. Various statistics are now merged for ranking purposes. Thus, there is now a unique impact factor for the various series or journals. This was more complex to pursue for the h-index, and obviously all affected series gained from that. However, this increased the scope of self-citations that could be removed for the impact factor calculations.
Note to RePEc archive maintainers: you can link your series or journals to others by adding a new field in your series templates, Followup: or Successor:, followed by the handle of the other series.
Expanded listings
Following a poll a few months ago, the portion of the rankings that is public has been expanded. This will be visible with the ranking released early next month. The ranking of authors and institutions within countries or US states passes from the top 20% to the top 25%, within fields from the top 5% to 10%. The big ones, the top 5% authors and institutions still includes the top 5% in much detail, but now also the next 5% in five 1% “bins.”
US Economics departments
While there is already a ranking of Economics departments, one of the most frequent requests is to have one specifically for the United States. There will be one starting with next month’s update. Link.
Lost authors
We sometimes lose track of some authors when their monthly messages bounce back. Typically this is because they have moved or died. In both cases, they should not be counting towards the ranking of the institutions they are affiliated with. For a few months now, they have not. By the way, you can help rectify their status or their address by alerting us. The list of lost authors is here. See also the known deceased authors.
Peer authors
Registered authors receive every month an email with an analysis of their rankings. This now also includes a list of about 20 peers that are similarly ranked.
Errata
There is no reason an erratum or a correction should count as an additional publication for an author. We now try to drop them from ranking considerations and also to link them to the original article.

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Posted by Christian Zimmermann

Volunteer appreciation: Volker Schallehn

March 15, 2010

Volker Schallehn is librarian at the University of Munich, but not your normal librarian. He has always been very active in open access, the free dissemination of research. For example, he has set up the institutional archive for the University of Munich, now one of the larger ones in the world, and doing so got so familiar with EPrints that he contributed code to this open-source project, along with a German translation of its interface.

His involvement with RePEc started when we were looking for a successor to the Economics WPA, which was holding papers for authors whose institutions or publishers were not (yet) participating in RePEc. Ekkehart Schlicht had the idea to add another repository to those Volker was already managing, hoping to exploit returns to scale. Volker agreed, seeing the broader mission in this initiative. Thus in 2006, the Munich Personal RePEc Archive was born, which now houses over 11,000 works and continues to grow steadfastly.

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Posted by Christian Zimmermann

Is there an alphabetical bias in citations?

March 11, 2010

In Economics, there is a tradition to list multiple authors in alphabetical order, unless exceptional circumstances call for a different order. This implies that “alphaberically challenged” authors like me often get forgotten, either because they disappear in “et al.” or because they become also-rans. RePEc manages to correct for “et al.” in citations, but it is possible that because later co-authors get less name recognitions, they also get less cited when sole authors. Using data from authors registered in RePEc, here is are some simple statistics that could shed some light, or raise some new questions.

I split the over 23,000 author into 26 bins, one for each letter of the alphabet corresponding to the initial of their last name. First, see how the average number of distinct works authors have written for each of those bins. The graph below runs from A on the left to Z on the right. While this is not a straight line, it does not appear to be obviously trending up or down. The correlation is -0.27.

Distinct works per author, by author's initial A-Z

Now look at the number of citations per author. This time, if you blink a little, you can see a little downwards trend. The correlation is -0.45 and note also that the spread is much larger.

Citations per author, by author's initial A-Z

Now try again with citations per work. A downward trend is now more visible, and the correlation is -0.53, with a different of about one citation between start and end of alphabet. Note that these are just simple averages, without any control for anything else that could correlate with the alphabet and lead to lower citation counts. But it is not obvious what such a control could be. Conclusion? Is there a bias in citations against alphabetically challenged authors? Possibly, but it is not a large one.

Citations per work, by author's initial A-Z

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Posted by Christian Zimmermann

RePEc in February 2010

March 3, 2010

The big news this month is that we reached half a million journal articles indexed on RePEc. We counted 816,240 file downloads and 2,781,710 abstract views, statistics that now include data from EconomistsOnline. Also, the NEP service had a record number of downloads by subscribers.

We also got 13 new RePEc archives: Università Bocconi (III), Technical University Darmstadt (II), London School of Economics (III), Trinity College, American Economist, Universidades Públicas de Andalucía, Economic Research South Africa, University of Cape Town (II), Review of Finance and Banking, Einaudi Institute for Economic and Finance, Romanian Society for Economic Science, Bruegel and Université de Neuchâtel.

Finally, in terms of threasholds passed, we can report:

500,000 indexed articles
160,000 working papers with references
30,000 registered people
6,000 indexed books

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Posted by Christian Zimmermann

500,000 journal articles listed on RePEc

February 25, 2010

The number of articles indexed on RePEc has recently surpassed half a million, with 88% linked to an online version. All these articles have been published in over 1000 journals listed on RePEc.

Journal articles now comprise the majority of the research material on RePEc, but this has not always been so. In fact, in the early days of RePEc, working papers (pre-prints) constituted the vast majority. But as commercial publishers started noticing how popular RePEc and its services were becoming, they wanted to be listed as well. They made the effort of converting their meta-data to our format and make it available at no charge. A few years back, this would have been unimaginable. Little by little, all major publishers opened RePEc archives. Nowadays, it is small independent publishers who join, along with various open access journals that look for free and efficient dissemination of their content through RePEc.

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Posted by Christian Zimmermann

About author rights

February 17, 2010

Authors are always very happy when their paper is accepted for publication in a journal, as this shows that their work was deemed important but editors and referees. But they also want to make sure that their work gets read and does not disappear behind a subscription wall. There are several steps an author can take here.

Retain copyright

The author is the copyright holder until this is transfered to someone else. Publishers asks very soon after a paper is accepted for publication that the copyright be transfered to them. Typically, the form asks for all rights, which implies that the author cannot use her own work in other publication or in presentations, even in her own classroom. There are two ways to avoid this: 1) ask for the “other” copyright form, which publishers provides upon request only. This form allows the author to retain certain rights. 2) amend the copyright form. SPARC has developed a standard form that is available here [pdf]. See further details regarding this procedure.

Keep pre-prints online

In many cases, a paper was previously made available online as a working paper. Do not remove it. Indeed, you are the copyright holder and do not have to relinquish this. Even if you did not follow the steps above, in most cases, you can still keep your working paper online. Many publishers have made public that they tolerate, to various degrees, that these pre-prints remain in place. You can check this at SHERPA/RoMEO.

Provide post-prints

You can even archive so-called post-prints. These are accepted versions on your article. Many universities and research funders actually require that post-prints be publicly archived, for example in an institutional repository. In Economics, it is also common to publish an accepted work in a working paper series. Again, to see what publishers officially allow in this respect, see SHERPA/RoMEO. You have more rights, of course, if you took steps to retain them.

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Posted by Christian Zimmermann

Volunteer appreciation: Venus Khim-Sen Liew

February 10, 2010

RePEc works thanks to a large number of volunteers, most of them toiling in anonymity. One who spends a lot of time on the project is Venus Khim-Sen Liew, currently Associate Professor of Economics at Universiti Malaysia Sarawak in Malaysia. Among many other professional responsibilities, he is editor at MPRA, the RePEc service that allows authors to upload their works to be indexed on RePEc, for those who do not benefit from a local RePEc archive. MPRA needs editors to ensure some quality control to make sure that submissions are of academic nature and satisfy copyright requirements. Venus is in charge of submissions in Malaya and in particular helps with those in English, of which a considerable number (over 9000) have been accepted so far, and much of it is the result of Venus’ work.

If you are interested in helping with RePEc as well, check out the volunteer opportunities.

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Posted by Christian Zimmermann

RePEc in January 2010

February 3, 2010

The big news for RePEc this month is the inauguration of a new RePEc service, EconomistsOnline, provided by Nereus who also contributes a major new archive of working papers to RePEc.

In terms of traffic, we counted 760,521 file downloads and 2,629,780 abstract views during the month. RePEc has welcomed 9 new archives: CASE (Poland), Johannes Gutenberg Universität Mainz, NEREUS, Universidade de Concepción, RSconsult, FrancoAngeli Editore, INFER, Agency for Economic Analysis and Forecasting (Bulgaria), Technological Educational Institute of Kavala

And finally, the thresholds reached during the month:

120,000,000 cumulated working paper abstract views
850,000 items listed
400,000 working paper announcements sent through NEP
333,333 working papers listed
275,000 working papers online
250,000 working paper abstracts
120,000 working papers with citations
4,000 series and journals listed

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Posted by Christian Zimmermann

Economists Online service launches in January 2010

January 28, 2010

[By Dave Puplett]

Economists Online is a new service that provides easy and open access to high-quality multilingual academic output in a single, cross-searchable portal. Economists Online contains research drawn from both the repositories of the project members and from the well established RePEc database.

The launch will be marked at the “Subject Repositories: European collaboration in the international context“conference in London on 28/29th January. Professor Nicholas Barr from The London School of Economics, who will be speaking at the conference, describes Economists Online as “A wonderful treasure trove of easy-to-find resources, all the more because so many can be downloaded directly”.

The Economists Online portal offers a search engine with a multilingual interface that can find both citations and full-text of a wide range of research, including articles, working papers, conference materials and datasets. In addition, the portal provides services such as RSS feeds, author profiles and publication lists. Abstract views and downloads through this portal are integrated into the statistics RePEc provides to users.

Economists Online was established by members of the Nereus Consortium, which consists of prestigious academic economic institutions in Europe and other leading Economics research institutes. Nereus is also providing full access to economic research from about 20 European institutions, both through Economists Online and RePEc.

1 Comment | Use of RePEc data | Permalink
Posted by repecblogguest

Why and how RePEc is free

January 22, 2010

RePEc is allowing free access to its services, to readers, authors and publishers. Why? Because we want that research be disseminated the most widely possible and in the most democratic way possible. Everyone should have the same chance at getting read, no matter where the author is located. And everybody should be able to access research, no matter what the means and the location.

Of course, we cannot make research completely free, as some publishers keep their material gated. But whenever possible, we offer alternative, open access versions to gated material. Those versions may not be the latest ones, but they are usually close enough and usable by readers.

But how can we make all those services available for free? For one, we have volunteers who are willing to devote some of their spare time for the cause. Also, the running of RePEc is decentralized to the furthest extend possible. For example, the actual indexing is done by the publishers (following these instructions). As they are the ones who benefit the most from being listed, they are willing to comply with our requirements. Thus the data input is costless to RePEc, and then the collected data is made available to those who would like to build a service with it. Again, volunteers create and manage these services at no cost to RePEc.

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Posted by Christian Zimmermann

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