That means that points have been assigned to the wrong groups. This may readily happen with a clustering method like cluster::clara() that uses a subset of the data to cluster a dataset too large to analyze as a unit. Negative silhouette numbers strongly suggest that your clustering parameters should be changed.
Sarah On Fri, Feb 19, 2016 at 6:33 AM, ABABAEI, Behnam <behnam.abab...@limagrain.com> wrote: > Hi, > > > We know that clustering methods in R assign observations to the closest > medoids. Hence, it is supposed to be the closest cluster each observation can > have. So, I wonder how it is possible to have negative values of silhouette , > while we are supposedly assign each observation to the closest cluster and > the formula in silhouette method cannot get negative? > > > Behnam. > ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
