It Slices! It Dices!

Experience is a great way to "reward" players who are motivated by seeing their character improve (and most players are, though some to a lesser degree than others). As such, I like to bias it toward game-improving behavior. Common systems include points based on the challenge/success in the plot (VERY common), the use of skills (Runequest, non-d20 Call of Cthulhu), or the GM-judged quality of play (usually shows up as a modifier not as part of the base system). Less common are the meta-game rewards (ADRP's diaries and logs, "bring the GM pizza and pop" house-rules, etc.), of which I am a fan only when they actually create useful behavior. (ADRP's one-time bonus for a promise in the future, for example, often fails to create any follow-on behavior, as I'm sure you've seen.)

A personal favorite of mine is to add in the "group enjoyment" factor. This was seen in the game Teenagers from Outer Space, where experience was based exclusively on a vote at the end of the session. By doing this, someone whose play made this session better gets more, someone who didn't doesn't.

Okay... it's 100% unrelated to a model of character learning, but it serves to reward desirable player behavior, so it meets my goal for an experience system. I personally converted this to other games, though it sometimes took considerable adjustment (for example, I had to scale GURPS experience by a factor of 10, so giving out 0.1 points at a time, so I could have the vote provide 0.0-0.4 points per session, singificant but not so much that it overwhelms all other factors).

Other ideas I like... Hero Wars has a couple clever ideas. One, as a balance item, is that it costs XP to "cement" an advantage gained during play. That is, if you find a major item or forge a new alliance or befriend a useful NPC, you must invest some XP in it/them or else they fade from the picture between episodes. I like this both for its game balance impact (PC who gets nifty new magic whatsit doesn't gain in skill as quickly as PC who doesn't) and its reflection of the "social overhead" resulting from new relationships. Another nice idea is that XP spent to improve/purcase abilities used in the story where the XP were earned are worth more than XP used toward other things (usually a factor of 2 is applied to costs). This biases us back toward the "improve what you use" system of Runequest without forcing quite so much detailed bookkeeping. "Improve what you use" results in a better model of learning (as much as XP is a model of learning) and, more importantly, in more story continuity.

Whew... that was pretty long-winded. Julia is right, I do need to set up my own blog for this sort of thing. (Or, rather, prod Jeanne forward a bit this weekend, as the installation of MT is supposed to already be in process.)