the opportunity cost of travel time. 



A TCM demand model also needs to include variables 

 reflecting income, preferences, and price and availability of 

 substitutes. For all of these terms, demand theory provides some 

 guidance as to the expected sign (direction) of the estimated 

 relationship to quantity demanded. These hypotheses are used 

 below to evaluate the estimated model. 



In order to use trip expenditures as a price variable, it is 

 necessary that travel cost be associated exclusively with the 

 opportunity to hunt a given site. To ensure this aspect of trip 

 homogeneity, the standard practice is to include only sample 

 trips that are mainly for purposes of hunting a specific site 

 (main purpose, single destination trips). As will be described 

 below, approximately 15% of our sample were excluded as either 

 multi-destination or multi-purpose trips. 



A final assumption necessary for the TCM model is that there 

 are no constraints on recreational use. In fact, only 19,550 

 nonresident deer tags (17,000 combination licenses and 2,550 deer 

 permits through special drawings) are sold each year. There is 

 currently excess demand for these nonresident licenses. 



In addition, the distribution of hunting pressure by area 

 for nonresidents is influenced by the system of special permits. 

 For example, in many hunting districts, deer can only be taken 

 if the nonresident hunter has drawn a special permit for that 

 area. On the other hand, there is no limit on the number of 

 resident deer tags. If all deer hunting in Montana were lottery 

 rationed, it would be possible to estimate the TCM model on 

 application data (Loomis, 1982). 



7 



