Hi there, when conducting a multidimensional scaling analysis, it is possible to do this on a correlation matrix? I calculated a dissimilarity matrix by substracting the corr.matrix from 1. Then I calculated the distance matrix with d <- dist(dissimilarity matrix) and ran the isoMDS function. Is that correct? In addition: The stress value was 2.9. I read that this is a percentage. So - according to the usual manner to report stress values from 0 to 1, this would be .029? Finally, I compared the solution (diagram) with the alscal-algorithm from SPSS (however computed on the raw data) and there were some slight differences. Can you tell me the differences between alscal and isoMDS? As you might see, I am not very experienced in MDS. Thus, any recommendation (literatur etc.) would be a great help. Thanks Holger -- View this message in context: http://old.nabble.com/Multidimensional-scaling-on-a-correlation-matrix-tp26126667p26126667.html Sent from the R help mailing list archive at Nabble.com.