I understand statistics and hypothesis testing. I also understand that many useful discoveries start as anecdotal evidence....after all, the hypothesis comes from observations, almost always. And I agree that this particular hypothesis is very difficult to test. But I'm a little tired of people saying, "I don't feel better after a Nitrox dive and there is no proof I should, so therefore no one feels better, it is all a myth."C'mon, you are a scientist!
The burden of proof is on the positive. I mean, it's fine to dive Nitrox, I always have, but not for that reason. If you run your NDLs to zero with EAN or air, you are going to have similar levels of decompression stress, you just get a longer dive on nitrox. If that's the cause of post dive fatigue (which I suspect), then you need to say why nitrox helps, and when it won't.
Why does the anecdotal evidence of people who think that it makes them less tired convince you, while you dismiss the anecdotal evidence of those who don't? Now if you could compare those two groups...
I do not dive to my NDL limits on a recreational dive, with or without Nitrox. So I suppose, given my typical profiles, I am ongassing less nitrogen when using Nitrox, and maybe that is why I feel better when using it. I could accomplish the same thing by using air on much shorter dives, but why would I want to? My two strongest pieces of personal evidence are: (1) many once-a-day air dives off Oahu to 90 ft (on the Mahi wreck) that inevitably pooped me, and (2) many multi-day multi-dive Nitrox dives on liveaboards and shore resorts that do not poop me.