Which answer would you select for this test question:
How many economists does it take to screw in a light bulb?
a. None. They’re all waiting for the unseen hand of the market to correct the lighting disequilibrium.
b. Two. One to assume the existence of a ladder and one to change the bulb.
c. Eight. One to screw it in and seven to hold everything else constant.
d. Irrelevant – the light bulb’s preferences are to be taken as given.
