I have a few friends who work at various studios, including one who writes up the contracts for writers, directors, actors etc.

There is no absolute formula -- each case can be different. Some stories are bought outright from the writer, "thanks, here's a check" and that's it. Other's may have involvement with the script or approval, some continue into development, and the pay can vary to installments, points, and any type of mathematic formula that would drive a Calculus Grad Student insane to figure out.

Prism Comics: Creating awareness and recognition for gay, lesbian, bisexual and transgender comics, characters, creators and fans.