13-9f The elasticity of demand per se has also no relevance for complementing goods (e.g., golf balls) as it relates to its complementary effect to the complemented (e.g., golf clubs)

“For example, an increase in the supply of golf balls will tend to cause a fall in their prices, which will tend to raise the demand schedule for golf clubs as well as to increase the quantity of golf balls demanded. This will tend to increase the price of golf clubs. For this effect the elasticity of demand for the original good (i.e., golf balls) has no relevance.”

Whichever good which does the complementing—the one that saw initial supply increase from the producer in anticipation of the complementary effect later for the complemented—is the original good in the quote above. In other words, in the example above, golf balls can be replaced with golf clubs, as long as golf clubs are replaced with golf balls.

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• 13-9g The substitutive effect will be mixed with the complementary effect, and the nature of each particular case determines which effect will be the stronger