I must not be understanding the difference, except that one is explicitly laid out -- the GM tells you these things are available -- and the latter is just left unsaid -- you pick something, whatever.
The difference is table expectations: if, for a given strategic decision, one is
expected to pick from those options laid out by the GM (obligating the PCs to follow the GM's lead on campaign direction), then that decision would be non-sandboxy and lower the campaign's sandbox percentage. If instead the
expectation is that it's ok for the PCs to make any strategic choice they want (obligating the DM to follow the PCs' lead on campaign direction), then that decision would be sandboxy and increase the campaign's sandbox percentage. (Campaigns run in a style where picking from a laid out list or making an open-ended decision is not a valid dichotomy for how IC strategic decisions are made simply wouldn't fall anywhere on the spectrum I've specified.)
Except, I've seen GMs claim even in plotted games that the players could just ignore the list and do whatever, and I don't know how that would be scored. There was a poster in this thread arguing that the WotC APs aren't railroads for precisely this reason -- the players could just abandon things and do something off script entirely. It would seem that this might be a hole in the conception?
That's why I'm focusing on campaigns rather than modules/APs/systems. Any given table running a module can decide how often to expect the PCs to follow the module, vs how often to expect the GM to adapt/expand the module's setting to accomodate whatever the PCs decide to do.
For example, a table could use a module and decide that when making top-level strategic decisions on what to do, the players are expected to choose to engage with the module's content. But that same table could simultaneously expect the GM to adapt to unorthodox ways to tackle the content in the book, including (e.g.) travelling off the module map to go on a diplomatic tour to raising a multinational army. That campaign would have a much higher sandbox percentage than a campaign where the table instead expects the players to not only choose to engage with the module's content, but also to stick to one of the expected paths through that content. Conversely, it would have a lower sandbox percentage than a campaign where the GM is expected to follow the players even if the players decide to ignore the module's content entirely.
Overall, I don't really see this construction as having a lot of merit outside of the endpoints -- the "spread" part of the spectrum seems very, very messy. The endpoints seems like not great fun either -- either CYOA book style play or complete lack of prompts at all. Most games I'm familiar with that are sandboxes still have hooks.
I'm cool with discussions on, and disagreements about, the spectrum's merits as an analytical/discussion tool. I'm just trying to show, against argument to the contrary, that the sandbox spectrum exists and has utility.
And sure, the middle of the spectrum is messy. It's definitely too messy (i.e. imprescise) to make it a useful large-scale cataloging tool, but I think it's still useful for comparing a small number of campaigns to each other (if all such campaigns are of a type that fits on the spectrum, of course). If there happens to be disagreement about which of two campaigns has a higher sandbox percentage, then the further analysis provoked by trying to place the campaigns on the spectrum will itself likely be illuminating, showing either disagreement about what the table expectations are for a given campaign, conceptual differences about what counts as an open-ended decision, or how/whether to weight certain types of decisions over others. In other words, I think the spectrum is useful
despite its messiness/imprecision.
