As others have mentioned here, both men were right, it depends upon how you look at the question.
When I first looked at this question, back in the days when PADI was still calling it "voodoo gas", I talked to researchers and statisticians about it.
As we know, Mark Twain famously said: "There are liars, damn liars, and then there are statistics." What the consensus on the subject was is that there is a very slight increase, statistically, on the side of safety if you use Nitrox but run Air Table times and depths. They all agreed, however, that it was so small as to be meaningless in practical terms.
The true benefits of Nitrox are (1) that it gives you more bottom time, and (2) that you feel better at the end of the day if you dive Nitrox. (That last is called "anecdotal evidence". This means that people in the field report it, but that the boffins don't have their name on the study yet!)
The DCIEM (now DRDC) tables have always been described as more conservative than others available, but the real arbiter of what is conservative in your case is YOU. No model can accurately judge how well hydrated you are, for instance, when you start any particular dive.
Hope that helps a bit. I would suggest that you take the nitrox class from the agency of your choice.
Cheers!
Rob Davie
When I first looked at this question, back in the days when PADI was still calling it "voodoo gas", I talked to researchers and statisticians about it.
As we know, Mark Twain famously said: "There are liars, damn liars, and then there are statistics." What the consensus on the subject was is that there is a very slight increase, statistically, on the side of safety if you use Nitrox but run Air Table times and depths. They all agreed, however, that it was so small as to be meaningless in practical terms.
The true benefits of Nitrox are (1) that it gives you more bottom time, and (2) that you feel better at the end of the day if you dive Nitrox. (That last is called "anecdotal evidence". This means that people in the field report it, but that the boffins don't have their name on the study yet!)
The DCIEM (now DRDC) tables have always been described as more conservative than others available, but the real arbiter of what is conservative in your case is YOU. No model can accurately judge how well hydrated you are, for instance, when you start any particular dive.
Hope that helps a bit. I would suggest that you take the nitrox class from the agency of your choice.
Cheers!
Rob Davie