We study communication in a two-player coordination game with Pareto-ranked equilibria. Prior research demonstrates that efficient coordination is difficult without communication but obtains regularly with (mandatory) costless pre-play messages. In a laboratory experiment, we modify...

When subjects can make non-binding announcements of possible contributions to a public good numerically, there is no effect on average level of contributions in a public goods experiment relative to play without announcements. But a detailed analysis of this experiment shows that pre-play...