Second, suppose that the estimates and bids are quite disperse. (Also
reasonable.) These two points imply that the highest bids (the shaded tail
in Figure 17.2) are above the true value of the item. On average, the
winning bidder loses money on the acquisition. At this point, you may ask
some of the high bidders in the class, whether this argument worries them.
(Do they still want to play for real or only for fun?) Find the highest bid.
Then, reveal the value of the item. With 20 or more students in the class,
nine times out of ten, the winning bidder will fall prey to the winner’s
curse, i.e. pay more than the item’s value. The only exceptions occur if
the class estimates are biased well below the true number of trinkets. (To
avoid this problem, try the trinkets in different shaped jars, and see that
the jar is 75% or more full.)
Having made the main point, you can raise some other questions.
What factors increase the likelihood and magnitude of the winner’s curse?
As discussed in the text, the winner’s curse increases with the degree of
uncertainty and the number of bidders. Does the winner’s curse happen in
real life? Yes, bidding for off-shore oil leases, competitive tender-offers,
and free-agent bidding for athletes are just three examples. How well did
you (the student) gauge your degree of uncertainty? Most individuals are
overconfident of their estimation abilities. Ask students if the true estimate
fell between their lower and upper bounds. Typically, less than half the
students answer in the affirmative by a show of hands. By construction,
the intervals should bracket the true value 90 percent of the time.
Students are surprised that their knowledge is so uncertain.
II. Teaching the “Nuts and Bolts”
This optional chapter contains a good deal of advanced material.
Accordingly, the instructor has a number of decisions concerning teaching
strategy.
A. In our view, the most important points include:
1. Optimal sealed-bids against a BCB distribution;
2. The winner’s curse;
3. The benefits of auctions.