Dear Phil, Gerard Bricogne pointed out a long time ago that the clearest comparison between two sets of phases is the complex correlation coefficient between two "best" structure factors ( m F exp(i phi) ) - this is equivalent to map correlation, but can be analysed in resolution bins.
I'm not sure whether there are programs which calculate this, though it's straightforward, and I've had various jiffy programs in the past (which I've probably lost) A while ago this was formally reported, including technical details, by Lunin & Lunina (1996), Acta Cryst., A52, 365-368, and they had at that moment some fortran program. In particular, this algorithm makes a key part of the low-resolution direct phasing approaches. With best regards, Sacha Urzhumtsev
