Peter,
I ran your earlier mail about shook swarms being less productive past Richard Ball, who found it interesting. His experience is that there is increased productivity, however his experience is confined to apiaries where EFB is present which, he says, always reduces productivity even if the EFB isn't visible.
Perhaps some of us could don our Santa hats and do our own controlled experiments and report. Who's going to set up a protocol and co-ordinate things? Not me as I've go far too much on at the moment.
Chris