In pre-written modules, there's often a "Scaling the Adventure" section, designed to help make a module written for four 5th-Level characters a challenge for a party of four 6th- or 7th-Level characters.
But what about larger parties? How do you scale an adventure to accomodate more PC's?
Surely the modifications wouldn't be the same. The capabilities of a party of four 9th-Level characters is different from a party of seven 6th-Level characters.