In  the authors proved the Pugh–Shub conjecture for partially
hyperbolic diffeomorphisms with 1-dimensional center, i.e., stably ergodic diffeomorphisms are dense among the partially hyperbolic ones. In this work we address the issue of giving a more accurate description of this abundance of
ergodicity. In particular, we give the ﬁrst examples of manifolds in which all
conservative partially hyperbolic diffeomorphisms are ergodic.