Scope (as opposed to a scope) is a meta trait of a campaign addressing how much of the setting it covers. This is a different issue from the scale of the campaign - you can deal with heroic matters concerning the future of the entire world (or even universe) without leaving your own town (Miss Summers…) or roam from planet to planet dealing with relatively trivial issues, however boldly you go about it.
A Local scope campaign is limited to a small part of the setting - one town or city and its environs or perhaps a small nation - although in some settings a single planet could qualify as local. All necessary adventures either come to this place, or are within easy commuting distance - excursions are rare and noteworthy. This can stretch verisimilitude a little (a single season of Inspector Morse tended to match Oxford's murder rate for a decade) but with the right location is entirely credible (especially if your locality is an international metropolis like New York, London or Hong Kong). Local campaigns lend themselves to well developed, recurring NPCs and plenty of detail and give the PCs lots of scope to develop local contacts, networks and inside information. In many cases they will be able to play home advantage against enemies.
A broad scope campaign wanders about across the length and breadth of the setting - a whole empire, planet, galaxy or multiverse. PCs are footloose and seasoned travellers, expected to follow the next clue to some far off place and make a temporary home wherever they hang their hat - or take their accomodation with them (especially in a seafaring campaign). These campaigns tend to score badly on recurring NPCs and deep engagement but are great for exotica, a new and interesting location every session and fantastic new creatures and challenges. PCs will need to develop adaptability, language and diplomatic skills and take the fight to enemies on their home turf.
Some degree of balance between the two is possible, but will often lead to a campaign that is neither one thing nor the other and feels somewhat lacking as a result.
Game and Story Use
- One possibility for a variable scope campaign may be to set it locally in a major city - say, classical Rome - which is also a major hub from which the PCs can be sent on occasional jaunts to remote places (Tarentum, Britannia, Egypt … Taprobane …) after which they return home to more local matters.