That isn't what I meant... I'm familiar with the XP system.
According to the Voting/Experience System node, I get a 25% chance of getting 2xp for being logged each day. I get a 25% chance of getting 1xp for every vote I cast. These methods of getting XP are not related to my writeups or my rep.
When I see that I have more XP in the XP nodelet, it doesn't tell me this is because someone voted up a writeup I've made, or if it's because I was logged on 24 hours ago. True, I can guess that if I get a +1 after voting, it was because of the vote, but if I leave a good post at 10PM, and log back on at 8AM, and see that I have 5 more XP, was that 5 from the rep alone, or 3 from the rep and 2 from the "logged on within 24 hours" scheme?
I can't tell from looking at the XP nodelet, or from my homepage, which XP is from signal, and which XP is from noise, so I can't calculate my S/N ratio.