phone call for interview at GSB

[apfphd]

I recieved a phone call from the economics track of a GSB (I'd rather not say right now, which one).
Can any of you guys tell me what they are trying to assess? They asked me why I had applied to a business program and I am afraid that I ended up conveying that my reasons for applying were weak.
Does anyone have any experience with any of this? What does this mean?
I'd really appreciate any feedback since it's one of my top choices at the moment.

Thanks!