(8th edition) (the pearson series in economics) robert pindyck, daniel rubinfeld microecon 529
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504 PART 3 • Market Structure and Competitive Strategy
F IGURE 13.2
PRODUCT CHOICE GAME
IN EXTENSIVE FORM
Crispy
Firm 2
Sweet
Firm 2
Crispy
Ϫ5, Ϫ5
Sweet
10, 20
Crispy
20, 10
Sweet
Ϫ5, Ϫ5
Firm 1
The Advantage of Moving First
In §12.2, we explain that the
Stackelberg model is an oligopoly model in which one
firm sets its output before
other firms do.
Recall that in §12.2, we
explain that in the Cournot
model each firm treats the
output of its competitors
as fixed, and that all firms
simultaneously decide how
much to produce.
In this product-choice game, there is a clear advantage to moving first: By
introducing the sweet cereal, Firm 1 leaves Firm 2 little choice but to introduce
the crispy one. This is much like the first-mover advantage that we saw in the
Stackelberg model in Chapter 12. In that model, the firm that moves first can
choose a large level of output, thereby giving its competitor little choice but to
choose a small level.
To clarify the nature of this first-mover advantage, it will be useful to review
the Stackelberg model and compare it to the Cournot model in which both firms
choose their outputs simultaneously. As in Chapter 12, we will use the example
in which two duopolists face the market demand curve
P = 30 - Q
where Q is the total production, i.e., Q = Q1 + Q2. As before, we will also assume
that both firms have zero marginal cost. Recall that the Cournot equilibrium
is then Q1 = Q2 = 10, so that P = 10 and each firm earns a profit of 100. Recall
also that if the two firms colluded, they would set Q1 = Q2 = 7.5, so that P = 15
and each firm earns a profit of 112.50. Finally, recall from Section 12.3 that in
the Stackelberg model, in which Firm 1 moves first, the outcome is Q1 = 15 and
Q2 = 7.5, so that P = 7.50 and the firms’ profits are 112.50 and 56.25, respectively.
These and a few other possible outcomes are summarized in the payoff
matrix in Table 13.10. If both firms move simultaneously, the only solution to
the game is that both produce 10 and earn 100. In this Cournot equilibrium each
firm is doing the best it can given what its competitor is doing. If Firm 1 moves
first, however, it knows that its decision will constrain Firm 2’s choice. Observe
from the payoff matrix that if Firm 1 sets Q1 = 7.5, Firm 2’s best response will be
TABLE 13.10
CHOOSING OUTPUT
Firm 2
7.5
Firm 1
7.5
10
15
112.50, 112.50
93.75, 125
56.25, 112.50
10
125, 93.75
15
112.50, 56.25
100, 100
50, 75
75, 50
0, 0
