Please go to http://beeinformed.org/participate/ and take the survey. It can be pretty involved depending on your specific case, but do what you can.
I just took the survey and am looking at some of the results from last year. Colony losses between different management styles (no non-bee derived products, natural only, prefer natural, use anything, other) were not statistically significant. In fact, the the range was between 31-36% with the first option rating at about 33%.
The difference between migratory and non-migratory was 30%, 34% respectively.
We see a lot of numbers in a lot of different directions, but the averages are not statistically different. I mentioned previously the differences between treating and non treating for varroa specifically were less than ten percent, I'm looking at the graph now and losses with no varroa treatment were 37% and treated were 29%, so only 8% difference. It's clear from the numbers that the ones who treated are more often commercial beekeepers, averaging 150 colonies, and the ones who didn't treat were less so, averaging 20 colonies.
According to the stats, powdered sugar was NOT helpful, actually increasing losses compared to whatever else was done.
Coumaphos only ~2.5% better than doing nothing.
Formic Acid, 6% better than nothing.
Fluvalinate, 2% better than nothing.
Miscellaneous herbal products, 3% better than nothing.
Small Cell, 1% worse than nothing on average, but varying widely. Using small cell in all colonies 2% better than in no colonies, but still widely varying. Shows a small bad correlation for going half way as it were.
SSB 2% better than nothing.
Here's an interesting one, drone removal, using it 1% worse than not using it. Dodged a bullet there.
Terramycin and Tylosin, 2% better than nothing.
Fumagillin and Nosevet, wash.
Again, I'm not seeing anything all the useful in treating to begin with. Most of these numbers say that the treatment does not do anything statistically significant. The best looking product is Formic Acid, but it is only correlated with increased survival by 6%. It's hard for me to see that a 6% increase justifies the cost and time it takes to treat. One thing treating does do is make for more consistent results.
On the other hand, many of us have experienced the 'going cold turkey' paradigm, both personally and vicariously. It must be noted that there is a big difference between going cold turkey and being cold turkey. So it may be that these numbers are more due to avoided losses from the switching process than differences in management. It's kind of like a tax on not changing.
Just a few thoughts.
Take the survey, get your information in there for this year's results. This information is helpful for all beekeepers.