*****  To join INSNA, visit  *****

I'm not sure about your electrons-people analogy, but I think the second
part of what you say isn't quite right.

The idea that 'empty central positions are a vacuum' is not served well
by your example of the removal of the 'second in command' from a
situation, because the second in command is a position described in
hierarchical rather than relational terms. Removing a person from a
network will have an effect related to relational as well as functional
role: if he or she is the only person linking two halves of a network
then removing them will be key--the matter (for both those trying to
maintain the network and those trying to disrupt it) then becomes one of
how easy it is to replace that person, in functional terms. Stopping a
flow (of information, or of HIV, or anything else) in any network would
ideally involve identifying all such points and removing them (as well
as, perhaps, removing those who could take the place of those already

I believe (though don't remember the reference--perhaps someone on this
list knows it) that the French made some progress in counter-terrorism
in Algeria by identifying forgers as key points in the networks of
insurgents and selectively 'removing' them. Such a strategy depends,
evidently, on having an awareness of both the attributional and
relational properties of nodes.


Dr Iain Lang
Epidemiology & Public Health Group
Peninsula Medical School
RD&E Wonford Site
Barrack Road
Exeter EX2 5DW
tel. +44 (0)1392 406749
email. [log in to unmask]

-----Original Message-----
From: Social Networks Discussion Forum [mailto:[log in to unmask]] On
Behalf Of Richard Rothenberg
Sent: 12 October 2005 17:25
To: [log in to unmask]
Subject: Re: Targeting critical nodes in criminal networks

*****  To join INSNA, visit  *****

Let me try out a thought with this group.  Predicting where an electron
is going to be at any instant is a statistical exercise, and carries
with it a certain measurable variability.  I don't want to strain the
metaphor, but a human network also changes (albeit a bit more slowly)
and predicting "where" an individual is going to be is also subject to
numerous sources of variation.  It may be that networks are great tools
for understanding the context in which persons are embedded, but not a
great tool for specifying exactly what any individual is going to be or
do.  In the area of disease dynamics and transmission, for example,
predicting who in a network will actually get HIV (or some other
transmissible disease) is problematic, as opposed to predicting which
individuals may be a greater risk because of their personal decisions
and network occupancy.

If this is a reasonable thought, than it casts the notion of "targeting
individuals" in a different light.  To be specific, targeting persons
may not make a lot of sense, and the results of "removing" a person from
a criminal network may or may not have the desired impact.  My guess is
that it won't, and that empty central positions are a vacuum just
waiting to be filled.  (In Iraq, there have been frequent announcements
that the second in command has been caught, but their capture seems to
have had little effect on the insurgency.)  But just as important, the
ethical and IRB implications--which are moot to begin with, and largely
a byproduct of the power IRBs have amassed--can also be cast in a
different light.

Rich Rothenberg

SOCNET is a service of INSNA, the professional association for social
network researchers ( To unsubscribe, send
an email message to [log in to unmask] containing the line
UNSUBSCRIBE SOCNET in the body of the message.