[R] How a clustering algorithm in R can end up with negative silhouette values?

[Sarah Goslee]

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.ABABAEI at 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.
>