Why is PDE being conducted as a field study rather than a laboratory study?
Decompression sickness (DCS) is a probabilistic phenomenon, as are cancer and heart disease. There are underlying causes for these diseases, but whether an individual suffers from disease is a matter of probability. Random chance is an important factor, just as when rolling “snake eyes” with a pair of dice. Statistical methods for estimating probability were first applied to decompression in 1984. These methods were complex and required accurate dive profile data and knowledge of DCS occurrence. Decompression trials in laboratory chambers provide the best controlled data for this purpose, but even with thousands of trials and hundreds of DCS incidents their number is insufficient to estimate DCS probability beyond reasonable question. Moreover, chamber trials are expensive, expose humans to risk of injury, and cannot investigate the effects of rapid ascent because chamber ascent rates rarely exceed 30-60 feet per minute. Observational field studies of open-water dives are an alternativ
