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On Sun, 2003-03-30 at 18:48, Steve Borgatti wrote:
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> BTW, this is kind of fun to play with interactively using NetDraw. In
> Ucinet, run Edge Betweenness. Then in NetDraw, open the edgebetweenness
> matrix as a network. Then in the Tie window, set the dichotomizing operator
> to LT and the cutoff to the largest edge betweenness value. Then repeatedly
> press the "-" button to systematically lower the cutoff. As you do, you see
> components emerge.
> steve.

My experience with UCInet is not great, but I believe the calculation
you describe is not the same as our algorithm, and our studies suggest
that in most cases it will not give useful results.  It appears to miss
out the step in which the edge betweennesses are recalculated following
the removal of each edge.  This step is crucial to the generation of
meaningful structure.

As far as I am aware, neither UCInet nor any of the other
general-purpose SNA programs can in their present form be used to
implement our method (other than laboriously performing the
recalculation step by hand).  Of course, it would be possible to add
code to UCInet to do so, and this might be sensible, seeing as the
method has been used by quite a number of people since its first
publication.  I'm assuming each group implemented their own version - at
least they didn't ask Michelle Girvan and me for our code - and this
seems like an unnecessary duplication of effort...

Best wishes,
Mark Newman.

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