Like Austin’s “performatives”, some models are used not merely to represent, but also to change their targets in various ways. This paper argues that Austin’s analysis can inform model evaluation: if models are evaluated with respect to their adequacy-for-purpose (Parker 2020), and if performativity can in some cases be regarded as a model purpose (a proposition that is defended, using mechanism design as an example), it follows that these models can be evaluated with respect to their “felicity”, i.e. whether their use has achieved this purpose. Finally, I respond to epistemic and ethical concerns that might block this conclusion.