In an effort to increase revenues, Sky Air recently partnered with several airlines to create a joint frequent-flier program. In the new program, miles earned on all partner airlines can be combined for reward tickets valid on any airline in the partnership. Sky Air's CEO cites a recent increase in the number of passengers on all the partner airlines as evidence that the new frequent-flier program is having the desired effect. Industry analysts doubt the CEO's claim. Which of the following, if true, best supports the analysts' positions?