Comparative Statics

Comparative statics is the analysis of how equilibrium outcomes change as a parameter of the model changes — most commonly the number of firms $N$, a cost parameter, or a demand-shifter. In Topic 4, increasing $N$ in a complementary-pricing game gives

so total price rises and quantity falls monotonically — the opposite of standard Cournot/Bertrand with substitutes.

When to use

Use a comparative-statics argument whenever an exam asks "what happens as $N$ changes?", "what happens if $A$ rises?", or "compare $N=1$, $N=2$, $N \to \infty$." Be explicit about the direction of change and quote the closed-form formula whenever one exists; the lecture's $N=1$ vs $N=2$ vs $N=\infty$ table is the model template.