Upgrading staff

[Footix]

I always look for staff with "natural" aptitude. Sometimes I have to go for staff with bronze badges, but they usually have no issues passing the qualifications to achieve a silver badge. However, moving from silver to gold is a real pain. If I have five staff members and have all of them do the exams at the same time, it's not unusual if only one of them passes the exam. 

So I'm trying over and over and over again.

Is it just incredible bad luck, or is it actually harder to go silver -> gold than bronze -> silver?

[Daniel Williams]

It is probably a combination of the 2, a bit of bad luck in your game, plus naturally it's going to be harder to reach the best coaching level (i.e. Gold). I think that's probably what's happening, unless @Marc Vaughan has anything else to add?