The point is that the basis for comparison is that all colonies in a study should be kept under identical conditions. To me, this seems so obvious that it doesn't need to be stated.
Your work is interesting and SUGGESTS that increased insulation aids winter survival but your sample size (If I remember correctly it was 3 colonies?) isn't enough to state categorically that we should all rush out and put lots of extra insulation on our colonies. I, for one, remain to be convinced. I think it could end up being a double edged sword (like most things in beekeeping) where pests and diseases could also flourish.
Is that correct? Is this the published work? And others experimental design is criticised. Blimey.
and
Solid floors are better than open mesh!! I really don't know where to turn.