Hi Michael,
Thanks for the reply.
I understand that the stress is a measure of how good the algorithm managed to represent the ordinal distances between items. And I also see why it's dependent on the number of dimensions.
I was hoping someone could tell me exactly what the formula for the percentual
stress is. To me it's not clear how this metric is calculated.
Regards,
Dieter
Michael Denslow wrote:
Hi Dieter,
I'll take a shot at this. As I understand it, the stress is telling
you how the ordination distances compare with original
dissimilarities that you calculated.
It is a measure how well your ordination has done in representing the
relationship of your sites. Note that the stress will differ
depending on how many dimensions are used. I believe the default is k
= 2 in isoMDS.
Hope this helps, Michael
Dear List,
I'm trying to interpret the results of the Kruskal's Non-metric
Multidimensional Scaling algorithm (isoMDS, MASS package).
The 'goodness of fit' is reported as "The final stress achieved (in
percent)".
What does this mean exactly? I've tried to google for an answer but
I've not come up with a definitive answer.
Regards, Dieter
-- Dieter Vanderelst PhD Student
Active Perception Lab University of Antwerp
http://batbits.webnode.com/
Postal Address: Prinsstraat 13 B-2000 Antwerp Belgium
Michael Denslow
Graduate Student I.W. Carpenter Jr. Herbarium [BOON] Department of
Biology Appalachian State University Boone, North Carolina U.S.A.
-- AND --
Communications Manager Southeast Regional Network of Expertise and
Collections sernec.org
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