I'm going to try my best to analyse it as best as I can.
Think of the application like an exam, with a pass mark of let's say 70%
Now let's say prior hosting experience gives you 30% plus or minus 5% depending on how well/often you host. (for example I host a lot but I had an event that went badly - which would do nothing but hurt my chances.
Ok let's look at your app, the app is just an expression of you and as such is now worth much. So let's say it's worth 10% if done well.
Your reputation counts for a lot, so it is worth at least 20%. If you're a known troll of sorts then that's going to hurt your application. But if you're a member who helps out with the community, has never had a bad experience or shown lack of maturity then you're going to get that full 20%. But say you're a person no one has really heard of. This will leave some mystery because without delving into your posts and infractions they won't know what kind of person you are.
Now lets' look at staff experience, if you're a local moderator than you've proven yourself as a responsible user who is capable of doing a job so this will give you at least 15%. But say you're another staff, like a clan moderator or a market squad. This will really prove your commitment and ability to punish suitably (you'll be used to handing out infractions at the correct times.) And further more you'll be known by everyone as you are already colored name staff. I'd be willing to throw that in as much as 40-50%.
But always remember that a lot of people will be meeting the pass mark so you have to get as high as a percentage as you can.
(This may be complete shit but I thought it was a simple way to explain things.)
A plethora of sources