Among those users of Primer, stress values greater than 0.3 are
interpreted as "questionable".  Using both isoMDS and metaMDS (vegan
package), the stress values returned are much higher using my own data
and using examples provided in R Help.  For example Rstress = 8.3, and
the stressplot r2 = 0.99 indicating (to me) that the ordination is OK.
I am guessing that the "stress" values across packages are not the same,
and googling about has not returned a satisfactory answer ... thus this
posting.  My concern being that reporting a stress value of 8 for what I
consider a satisfactory result may raise a few Primer-user's eyebrows.

 

Gregory A. Graves, Lead Scientist

Everglades REstoration COoordination and VERification (RECOVER) 

Restoration Sciences Department

South Florida Water Management District

Phones:  DESK: 561 / 682 - 2429 

                   CELL:  561 / 719 - 8157

 


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