 An act is morally wrong, then, if it is blameworthy, i.e., if it would be proper to blame an agent for performing that act. The question, of course, is what grounds such norms of blame. Interpreters have in general taken Mill to believe that whether we ought to blame an individual for any given act—and whether, therefore that act is morally wrong—is determined by considerations of utilitarian efficiency. An act is wrong, therefore, if it would be productive to overall utility to blame an individual for performing that act—or, under a rule-focused interpretation, if it would be productive to overall utility for there to exist a rule to the effect that individuals performing actions of that sort were subject to  blame.[5]