We have anecdotal evidence that bonus disqualification standards for co-branded cards (Delta, Hilton, Marriott) are different than the standard for American Express' proprietary cards (Platinum, Gold, Green, Blue, Everyday). If this is accurate, approval or disqualification in one category may not tell us much about the other, and they may need to be regarded as two separate data pools.

I assume American Express would track abandoned applications, and abandonment would be evidence that the applicant is primarily interested in the bonus.