LISTSERV mailing list manager LISTSERV 16.0

Help for SOCNET Archives


SOCNET Archives

SOCNET Archives


SOCNET@LISTS.UFL.EDU


View:

Message:

[

First

|

Previous

|

Next

|

Last

]

By Topic:

[

First

|

Previous

|

Next

|

Last

]

By Author:

[

First

|

Previous

|

Next

|

Last

]

Font:

Proportional Font

LISTSERV Archives

LISTSERV Archives

SOCNET Home

SOCNET Home

SOCNET  May 2007

SOCNET May 2007

Subject:

Re: Arbitrary removal of nodes in reg eq-analysis?

From:

Martin Everett <[log in to unmask]>

Reply-To:

Martin Everett <[log in to unmask]>

Date:

Wed, 23 May 2007 13:02:17 +0100

Content-Type:

text/plain

Parts/Attachments:

Parts/Attachments

text/plain (120 lines)

*****  To join INSNA, visit http://www.insna.org  *****

Carl

First of all the workings of REGE are not all together clear and you may be
attributing an accuracy to the results beyond what is there. In particular
the three iterations is left over from the days when computing these values
was very slow. You may get rather different results if you increase from the
three iterations. However, let us assume that what you have done is correct
and the partitions do indeed reflect regular equivalence classes.

At the first stage you do not give any information about the relationships
between the groups you find and the rest of the network. From a structural
point of view these positions must be significant but at the same time you
indicate they are marginal.

Suppose this was a friendship network and the values of the links represented
strength of friendship. If one group have  weak links to an individual and
another group have say no links to the same individual and further suppose
the groups have stronger internal ties and stronger ties to each other
(across the groups) than to the outsider. Then REGE will focus on the
structural properties of the outsider and place the outsider in a single
group before looking at the differences in the two groups. It will then find
the two groups because of their different relationship with the outsider. But
these two groups may not be two groups since they only have weak links to the
outsider. Since REGE does not rank strength but looks for similarity of ties
then it has formed the groups on very weak evidence. In this case it is quite
legitimate to remove the outsider and look for the structure which represents
the patterning without the excluded individual.

In other words what you do is completely justifiable provided the groups you
remove are really marginal and not just inconvenient. 

In essence you need to determine if these nodes are really peripheral and if
they are then you are OK. If they are not then you really should not do this.

Martin


Martin Everett



-----Original Message-----
From: Social Networks Discussion Forum [mailto:[log in to unmask]] On
Behalf Of Carl Nordlund
Sent: 22 May 2007 15:29
To: [log in to unmask]
Subject: Arbitrary removal of nodes in reg eq-analysis?


*****  To join INSNA, visit http://www.insna.org  *****

Hi all,
Having a little dilemma here which I guess others before me have 
confronted. Being self-taught in everything SNA, I pose my question to 
this email list, hoping for some tutoring on the subject!

I'm currently doing a reg. equivalence analysis on energy flows (energy 
content in four fuel commodities) between the countries of the world - 
data is valued, directional with quite a large value span among the flow 
values. Using the REGE-algorithm in the Ucinet package, 3 iterations, 
selecting the number of partitions based on an Anova Density check for 
different number of partitions (as used in Luczkovich et al).

When using 99 countries in my dataset, I get an optimal split at 11 
partitions (i.e. positions containing role-equivalent actors). Two of 
these are singleton positions, i.e. containing only singular countries, 
and two positions contain only two countries each. All these 6 countries 
are fairly small and uninteresting, covering only 0.27% of total world 
population, 0.04% of total world GDP, and 0.03% of total flow values in 
the dataset.

Thus, what I would like to do is to remove these 6 countries from my 
dataset and repeat the analysis with only 93 countries. When doing so, I 
get an optimal number of positions at 8, the two smallest of these 
positions containing 3 and 4 countries respectively. I find this 1) much 
easier to analyze, 2) much easier to visualize (as a reduced/image 
graph), 3) giving a higher resolution (more partitions) regarding the 
positions containing the bulk of countries, and 4) removing countries 
that I feel could "disturb" the REGE algorithm in finding the major 
positions, removing countries that though might be unique but not very 
significant with respect to their coverage (as given by share of total 
flow values and attributional measures such as population and GDP).

However: how on earth can I motivate this? Can I just simply argue that 
"well, first I included these 6 countries, but as these countries 
resultet in 4 unique positions containing only these countries, I chose 
to remove these countries from the dataset and try without them - they 
are so small and insignificant anyhow..."? I could probably find some 
criteria for removing these based on their attributes, net degrees or 
similar, but that would not be very scientifically honest now, would it?

How have other people done in analyses that yields a bunch of trivial 
and singleton positions, i.e. positions that only contain 1-2 actors 
that are of fairly minor importance anyway? Suggestions?

(And sorry for using this email list as a classroom here - I have 
nowhere else to turn to...)

Yours,
Carl

-- 
Carl Nordlund, BA, PhD student
carl.nordlund(at)humecol.lu.se
Human Ecology Division, Lund university
www.humecol.lu.se

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

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

Top of Message | Previous Page | Permalink

Advanced Options


Options

Log In

Log In

Get Password

Get Password


Search Archives

Search Archives


Subscribe or Unsubscribe

Subscribe or Unsubscribe


Archives

November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008, Week 62
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006
April 2006
March 2006
February 2006
January 2006
December 2005
November 2005
October 2005
September 2005
August 2005
July 2005
June 2005
May 2005
April 2005
March 2005
February 2005
January 2005
December 2004
November 2004
October 2004
September 2004
August 2004
July 2004
June 2004
May 2004
April 2004
March 2004
February 2004
January 2004
December 2003
November 2003
October 2003
September 2003
August 2003
July 2003
June 2003
May 2003
April 2003
March 2003
February 2003
January 2003
December 2002
November 2002
October 2002
September 2002
August 2002
July 2002
June 2002
May 2002
April 2002
March 2002
February 2002
January 2002
December 2001
November 2001
October 2001
September 2001
August 2001
July 2001
June 2001
May 2001

ATOM RSS1 RSS2



LISTS.UFL.EDU

CataList Email List Search Powered by the LISTSERV Email List Manager