I was referring to the bolded portion of the equation. Which you'd know, if you'd been reading my posts. Pet. Peeve.
That's one wall-of-text post in a multi-page thread, and one that's unlinked to any of the posts that it is in reply to. Is it really so surprising people missed it?
The problem WotC have is that they cannot just ignore the second half of you equation, because setting a baseline according only to that first half renders it utterly meaningless.
The designers at WotC are well aware of the value of the levelling mechanic to the game. They're also well aware that there are constraints on the frequency of levelling. Too fast, and people don't get to properly try out their new toys; too slow, and the whole thing just becomes a grind.
And these are
real-time constraints on levelling - they work in terms of hours played, sessions per month, and even the length of the campaign.
Now, as discussed, those XP advancement tables and the reward levels for creatures represent a baseline for progression. Which means that WotC
will have to set one. That being the case, and since that baseline has to account for the real-time issues noted above, WotC will have to make some assumptions. Once they get to that point, we're all better off if they make the best assumptions they can.
So, yes, they should aim to find out how long, on average, groups play for, how frequently, on average, they play, and so on and so forth. And thus, set the baseline that is closest to 'correct' based on those averages.
But then, to make the tool
really useful, they should provide the DM with the advice he needs to tailor the system to his group: "We have assumed
this many encounters per hour,
that many hours per session,
so many sessions per month, and a campaign spanning
some months will gain the PCs
some levels. Since your group probably doesn't match this exactly, here's now to adjust the XP rewards..."
That way, instead of us all just being given a meaningless jumble of numbers that someone at WotC picked because they 'feel right', we get something that has some thought behind it that we can then tailor accordingly.
Your formula, that
The equation for how many levels a PC gains in an arbitrary length of time (we'll call it a month) looks like this:
levels/XP * XP/encounter * encounters/hour * hours/session * sessions/month
is probably not too far from being right. And you're also right that the differences between groups increases along with the terms. But that doesn't actually matter - WotC don't need to provide the perfect system for all groups. All they need to do is give me the equation and
I'll plug in the numbers for my group.