A collaboration graph for E-LIS

1. Thomas Krichel Long Island University & Novosibirsk State University & Open Library Society 3 November 2011 A collaboration graph for E-LIS

2. Introduction • Thanks • Ángel Sánchez Villegas for usage of the e-lis domain. • To Tomas Baiget, who has encouraged me to present here. • Warnings • Data shown here were correct as of 1 November 2011. • I am glossing over some technical details. • Over 30 slides

3. overview • Introduction to AuthorClaim • Introduction to a co-authorship network based on restricting AuthorClaim to E-LIS documents • Web interface and campaign

4. a known problem • In publishing systems such as E-LIS, the authors are usually entered by name. • It is well known that the name of an author does not identify a author • multiple ways to express the name of the same person • multiple people sharing one expression of their names

5. a tried solution • One way to partially solve this problem is to have a system where authors can • claim papers that they have written • disclaim papers written by their homonyms • The first system of this kind was the RePEc Author Service • created by Thomas Krichel in 1999 • now has registered over 30000 economists

6. AuthorClaim • AuthorClaim is an interdisciplinary version of the RePEc Author Service. • It was created by Thomas Krichel in 2008. • Lives at http://authorclaim.org. • Over 100000000 authorships of over 35000000 documents can be claimed. • Among the documents are the E-LIS papers.

7. 445 E-LIS papers claimed … • 72 Tomas Baiget • 61 Ulrich Herb • 43 Antonella De Robbio • 39 Thomas Krichel • 26 Andrea Marchitelli & fernanda peset, • 20 Ross MacIntyre • 16 Dirk Lewandowski • 15 Bożena Bednarek-Michalska • 14 Lidia Derfert-Wolf • 11 Zeno Tajoli & Imma Subirats

8. by 36 authors • 9 Derek Law & Emma McCulloch & Philipp Mayr • 8 Jeffrey Beall • 7 nuria Lloret Lloret Romero • 6 Benjamin John Keele • 5 Adrian Pohl & Maria Francisca Abad-Garcia • 4 Walther Umstaetter • 3 Andrea Scharnhorst & Jose Manuel Barrueco & Thomas Hapke & Christian Hauschke & Klaus Graf • 2 Frank Havemann & Eberhard R. Hilf & Bhojaraju Gunjal & Chris L. Awre • 1 Loet Leydesdorff & Peter Bolles Hirtle & Alexei Botchkarev & Christina K. Pikas & Oliver Flimm & Sridhar Gutam

9. so far so good • I don’t really want to talk about AuthorClaim but about a services that we can build when we have identified authors. • When we have this data, we can find out who has been writing papers with whom. • In other words we can study the co-authorship network.

10. co-authorship • When two registered author claim to have authored the same paper, we say that they are co-authors. • The authorship relationship creates a link between the two authors. • The link is symmetric, meaning that the fact that Thomas is a co-author of Imma means that Imma is a co-author of Thomas.

11. 58 papers have been co-claimed … • 12 fernanda peset • 10 Tomas Baiget • 8 Imma Subirats • 6 Antonella De Robbio • 4 nuria Lloret Lloret Romero

12. by 16 co-authors • 2 Andrea Marchitelli & Ulrich Herb & Ross MacIntyre & Bożena Bednarek-Michalska & Thomas Krichel & Dirk Lewandowski & Lidia Derfert-Wolf • 1 Derek Law & Emma McCulloch & Sridhar Gutam & Philipp Mayr

13. network and components • When we start with one co-author, and we move to her co-authors, what other authors can be reach? • We call the authors we can reach by starting from any one of them by following co-authorship relationships a component of the network.

14. components in the network • “Scottish”: Derek Law & Emma McCulloch • “Polish”: Bożena Bednarek-Michalska & Lidia Derfert-Wolf • “German”: Dirk Lewandowski & Sridhar Gutam & Philipp Mayr • “Giant”: Andrea Marchitelli & Ulrich Herb & Thomas Krichel & Antonella De Robbio & fernanda peset & Imma Subirats & Ross MacIntyre & nuria Lloret Lloret Romero & Tomas Baiget

15. the giant component • The size of the giant component is larger than the combined size of all other component. • It is very common, in real existing networks, that there is a giant component. • As the network grows, older small components join the giant component and new small components are created. • We therefore study the giant component.

16. centrality • Who is at the center of the E-LIS author network, i.e. the most central author in E-LIS? • The answer is that it depends on how we measure centrality. • Two measures are commonly used • closeness centrality • betweenness centrality • Both depend on a measure of distance

17. distance • To understand that we need a measure of distance. • We say that two authors have distance one if they are co-authors. • We say that two authors have distance two if they are not co-authors, but have a common co-author. • etc

18. distances for Imma Subirats • Tomas Baiget 1 • Antonella De Robbio 1 • Ulrich Herb 2 • Thomas Krichel 1 • nuria Lloret Lloret Romero 2 • Andrea Marchitelli 2 • Ross MacIntyre 2 • fernanda peset 1 • Imma Subirats 0

19. distances for Ulrich Herb • Tomas Baiget 1 • Antonella De Robbio 3 • Ulrich Herb 0 • Thomas Krichel 2 • nuria Lloret Lloret Romero 3 • Andrea Marchitelli 4 • Ross MacIntyre 4 • fernanda peset 2 • Imma Subirats 2

20. closeness centrality • The average distance of Imma is much small than the average distance of Ulrich. • In fact, we can calculated to average distance of the every author from all other authors. • This is what we call closeness centrality of an author.

21. shortest paths • In order to find the distance between two authors, we have to evaluate all possible paths between them. • We need to find shortest paths between. There are well-known algorithms to find them. • The distance is the length of the shortest path.

22. diameter • When we have found all shortest paths, we can find the length of the longest shortest paths between any two authors. • This is called the diameter. • In our network the diameter is four. • This much smaller than the number of authors in the giant component (16). • We say that our network has the “small world” property.

23. shortest paths from Tomas Baiget • → Thomas Krichel • → fernanda peset → nuria Lloret Lloret Romero • → fernanda peset • → Imma Subirats → Antonella De Robbio → Ross MacIntyre • → Ulrich Herb • → Imma Subirats → Antonella De Robbio • → Imma Subirats → Antonella De Robbio → Andrea Marchitelli • → Imma Subirats

24. shortest paths from Antonella De Robbio • → Imma Subirats → fernanda peset → nuria Lloret Lloret Romero • → Imma Subirats • → Imma Subirats → Tomas Baiget → Ulrich Herb • → Imma Subirats → Tomas Baiget • → Imma Subirats → fernanda peset • → Andrea Marchitelli • → Ross MacIntyre • → Thomas Krichel

25. shortest paths from Ross MacIntyre • → Antonella De Robbio → Imma Subirats → fernanda peset → nuria Lloret Lloret Romero • → Antonella De Robbio → Imma Subirats → fernanda peset • → Antonella De Robbio → Imma Subirats → Tomas Baiget → Ulrich Herb • → Antonella De Robbio → Thomas Krichel • → Antonella De Robbio → Imma Subirats → Tomas Baiget • → Antonella De Robbio → Imma Subirats • → Antonella De Robbio • → Andrea Marchitelli

26. what do the paths tell us? • We find that some authors are appearing more often as intermediaries than other authors. • In fact, we can evaluate the number of times an author appears as an intermediary in the paths. • This is what we call the betweenness centrality of an author. • A large number of authors have a betweenness of zero. They are called marginal authors.

27. summary • We build a network. • We find two ways to evaluate authors • closeness • betweenness • Now let us look at the results.

28. ranking for closeness rankname closeness • 1 Imma Subirats 1.5 • 2 Antonella De Robbio 1.75 • 2 Tomas Baiget 1.75 • 2 Thomas Krichel 1.75 • 5 fernanda peset 1.875 • 6 Andrea Marchitelli 2.5 • 6 Ross MacIntyre 2.5 • 8 Ulrich Herb 2.625 • 9 nuria Lloret Lloret Romero 2.75

29. ranking for betweenness rankname betweenness • 1 Antonella De Robbio 2.7 • 1 Imma Subirats 2.7 • 3 Tomas Baiget 2.025 • 4 fernanda peset 1.575 • Andrea Marchitelli, Ross MacIntyre, nuria Lloret Lloret Romero, Thomas Krichel, Ulrich Herb are all marginal.

30. web service • E-LIS and AuthorClaim data are readily available in bulk. • There is a software called icanis, developed by yours truly, that can calculate and visualize results. It is configurable via XSLT. • Almost instantaneous updates are in principle possible, but not implemented.

31. coll.e-lis.org • This is a site that I have set up. • I think we need a site in the rclis domain but I am not sure what the name should be. • coll.e-lis.org is a bad name too. • So this is meant as a prototype.

32. features • Rankings for closeness. • Full path searching from author pages • with support for partial name entry • but within there no highlighting for parts • Unclear documentation

33. ranking • Ranking is the way forward with populating scholarly communication services. RePEc has shown this time and again. • Co-authorship ranking is particularly interesting because authors have to convince their co-authors to publish papers in E-LIS and to claim them in AuthorClaim.

34. campaign • We need to do some work on the site. • Then we can have campaign and award a cash prize. • I am thinking about donating $200 to the top of each category or $300 to joint winner. • The competition would be time-limited, say about three months next Summer. • During that time we would do frequent updates of the site.

35. Thank you for your attention! http://openlib.org/home/krichel write to krichel@openlib.org