  In this paper we study empirically the validity of measures of referential
success for referring expressions involving gradual properties. More
specifically, we study the ability of several measures of referential success
to predict the success of a user in choosing the right object, given a
referring expression. Experimental results indicate that certain fuzzy measures
of success are able to predict human accuracy in reference resolution. Such
measures are therefore suitable for the estimation of the success or otherwise
of a referring expression produced by a generation algorithm, especially in
case the properties in a domain cannot be assumed to have crisp denotations.
