The RePEc Author Service (RAS)
allows for authors to identify, or 'claim', papers they have written in the
RePEc digital library.
When two authors claim the same paper,
they are co-authors. The relationship of co-authorship
creates a network between most authors. The shortest paths in that network between
different pairs of authors are of different lengths.
Between co-authors, the shortest path has length one;
when two authors have each written with a third author, but have not written
a paper together, the shortest path relating those two is of
length two, and so on.

There must be at least one author for whom the average length path
to all others in the network is the minimum. This author will have the highest
closeness ranking.

There must be at least one author who appears on the largest number
of shortest paths between any two other authors. This author will have the highest betweenness ranking. A number
authors are marginal, i.e., they are not on a shortest path between any
other pair of authors. CollEc does not report a betweenness rank for them.

This is a binary network. Two authors are linked if they have
claimed at least one paper in common in RAS. CollEc
calculates paths using an extension of Dijkstra’s algorithm.
The extension allows for the calculation of all shortest paths
between two authors, rather than just one as the standard
algorithm would do. For some couples of authors, this leads to
large sets of shortest paths. Shortest path multiplicity would
clog the user interface of CollEc. Fortunately most of the
multiple binary shortest paths can be eliminated when we take
collaboration strength as a secondary criterion. The
elimination of these shortest paths does not impact closeness
centrality rankings but it does impact betweenness centrality.

This site is maintained by me, Thomas Krichel. It
should be fully functional and usable. If you notice a bug
or have questions, please get in touch. Note that the site will
never be fully accurate, because the calculations involved take
a very long time. The results will therefore always lag over the
state of the co-authorship network.