Diamonds have value mainly in exchange.
Water has value mainly in use. Currency accurately measures the value of diamonds, but not of water. Cost-effectiveness analysts do interviews to elicit preferences about different states of health. The problem is that Volk and coworkers also interviewed the wives of these 20 men and on that basis generated a remarkably different utility outcome of 0.98. Volk and colleagues also cited reports in which physician expert interviews generated utility values of 0.60, 0.95, and 0.85.