Does Ignoring Multi-Destination Trips in the Travel Cost Method Cause a Systematic Downward Bias?

In theory, treating the multi-destination trips (MDTs) as single-destination trips (SDT) does not necessarily lead to biased results, because negative effect of price increase may be offset by the shift of the estimated demand curve. However, in our empirical application of the TCM zonal model to the valuation of the economic benefits of the Bellenden Kerr National Park in Australia we find (statistically significant) evidence that ignoring the MDTs leads to a dramatic overestimation of the consumer surplus. This is in sharp contrast to the earlier empirical evidence from other type of TCM models, which have either excluded the MDT visitors from the data set or treated them as single-destination trips, suggesting the opposite conclusion.