On the adequacy of scope test results: Comments on Desvousges, Mathews, and Train

- We conducted a contingent valuation study involving water pollution.
- Desvousges et al. (Ecological Economics, 84, 121-128) criticize our scope test.
- They find that our results show inadequate responsiveness to scope.
- In fact, they misinterpret what we did.
- After correcting the misinterpretations, their critique proves invalid.

Desrvousges et al. (2012) investigate criteria for judging the adequacy of scope test differences in contingent valuation studies. They focus particular attention on our study (Chapman et al. 2009), arguing that, while it demonstrated a statistically significant scope effect, the effect is too small. Unfortunately, DMT misinterpreted Chapman et al., an error that makes DMT's criticisms of our study invalid.