Natural gas ranks second only to crude oil as a primary source of energy in North America, During recent years, gas has satisfied 25 percent of all energy requirements in the United States. Most of this gas has been produced domestically, but 5 to 10 percent has been supplied by pipeline imports...

Consumers' choices tend to display greater variety when made for future versus immediate consumption. Previous accounts of such diversification differences suggested that they are driven primarily by (deterministic) shifts in underlying preference. Through a series of simulation studies, we...