A Note on the Functional Form of Travel Cost Models with Zones of Unequal Populations
检验了半对数旅行成本模型是否存在异方差问题，发现其几乎不存在异方差，而线性模型则存在严重异方差，因此半对数形式更适合该应用。
Bowes and Loomis have recently shown that the linear travel cost model contains heteroskedastic errors, and they have presented a correction procedure for the linear model.Since the semilog functional form has been used in other studies of recreation demand, this paper addresses the question of whether the semilog model requires a correction procedure for heteroskedasticity.Statistical tests indicated that heteroskedasticity was virtually nonexistent in the semilog model estimated by OLS, even though serious heteroskedasticity was detected in the linear model.The semilog form was also indicated to be empirically appropriate for this application of the travel cost method.