Before revision:  The DM maximizes his or her continuation value under a worst-case model which lies within a nonparametric neighborhood of a benchmark model  .
After revision:  The DM maximizes his or her continuation value under a worst-case model which lies within a nonparametric neighborhood of a benchmark model that he or she fears is misspecified by a set of models. Decisions are evaluated under a "worst-case" model that delivers the lowest utility among all models in this set .