Mind changes: post script
Actually, I wonder about this mind changing business....
Two correspondents, Julian Echave, and another, privately, questioned the crudeness of this concept.
One way of responding to what they said is to note that, for example, from a Bayesian perspective, the binary shift in beliefs is a bit of a nonsense.
Mind changing perhaps could mean, from this perspective: given a binary choice between two policy options [say, minimum wage or no], my posterior probability mass on the event that a minimum wage of a given level would have such and such an effect on employment outcomes shifted - in the light of evidence - such that my binary choice shifted from preferring no minimum wage, to supporting one.