The chapter made extensive use of empirical examples from the Iowa lakes project. Using these examples complete the following:

(a) Summarize the range of welfare estimates for similar scenarios from the three different models. Note the places where the predictions are similar and different, and speculate on what could be driving these differences. Imagine different uses for these estimates, and discuss how the differences in predictions may or may not be important for the different uses.

(b) Examine the suite of models and results, and distinguish the findings that you find credible and those that you do not. In particular, consider the identification assumptions needed for each model and discuss potential threats to the validity of the estimates.