Rather than end the investigation at this point, I would recommend that the entire scheme be repeated, say 1000 times. Each time a distribution of doses would be obtained, but these distributions would vary because new values for diet, food concentrations, calcium, c, g, and time. would be generated each For each of these 1000 distributions we could compute x and 3x. If, in all 1000 cases, 3x was greater than 95 or 99 percent of the distribution, then we might begin to have some confidence in the 3x approach. It's clear, of course, that the results of this type of exercise will not settle the issue of whether 3x is or is not a good technique. might only serve to muddy the water and cause confusion. In fact, it On the other hand, if the 3x rule worked well even under the most extreme and worst cases possible, it could be very encouraging. The above scheme is very sketchy and needs to be gone over and revised by someone who is more familiar than I with the evaluation of dose models. Chet Richmond or Chet Francis might be able to suggest someone from Oak Ridge who could assist and advise LLL in such a project (Dr. Charles T. Garter, ORNL, would, in my view, be qualified.) I will be on vacation in Michigan from July 17-30 and hence won't be available during that time to discuss this memo. I wanted to get it in the mail before I left so that if other members of the Advisory Group agreed with me that the matter was worth pursuing, it could get underway during July.