Hi Joe and Everyone, I might have missed something here, but will respond. >I don't think this can be attributed to clean comb alone. How can one be sure that the accompanying brood break does not factor in? There wasn't any break in the brood cycle. A deep box of clean, large cell comb was inserted above the broodnest. >Or the elimination of mite infested drone brood? No frames with brood in them were eliminated. >Or reorganization of broodnest? No broodnest reorganization occurred. >Or weeding off of varroa and other disease by artificial swarming? No shakedown were used. >Or the elimination of contaminated comb? No contaiminated comb. Both the large and small cell combs had never been treated with anything before the test. >Could also be the open broodnest effect,,, aiding the colonies ability to out brood mites and disease,,, Bro. Adam does state that "an open broodnest is essential,,," I run all my vertical hives in three deeps. And I use a checker board approach which keeps broodnest interference to a minimum. Both the large cell and small cell hives were run exactly the same way. The only thing that differed was the cell size. They weren't even requeened which resulted in some problems and a termination of the experiment three years into the test. Different beekeepers using other management techniques and equipment might get different results. Regards Dennis -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---