The gains from combining travel cost and contingent valuation data to value nonmarket goods

This paper provides a critical assessment of the improvements in precision and bias to welfare measures from combining contingent valuation and travel cost data. Simulation experiments are performed using a variation of the model first suggested by Cameron (1992a) with a focus an identifying likely lower bounds on these gains. fn addition to examining single-bounded contingent valuation as a component of the combined model, this paper investigates additional gains that may accrue from employing a double-bounded variant of contingent valuation. Sizable gains in both bias and precision are found in the simulation experiments. The results suggest that additional investigation into these models is warranted.