This question was raised at the latest session of my D&D group. I just changed my PC, so I got the xp penalty the Dungeon Master's Guide suggests (a little less than that, to be precise). To clarify things: I talked to the DM about the fact that -- as stated under the rule about the penalty in page 42 of the DMG -- a character of lower level in a group of equal-level characters gets more experience if they all defeat a CR appropriate monster… a rule made to narrow or close the experience gap.
Then, the drow of the group suggested that, if that were true, he should be gaining more experience as well. The sidebar on page 42 does not clarify if it is based on Effective Character Level; it says level 9 characters in its example.
What is the case? Does the rule exist, and is it based on ECL, on Class level, or an option I do not cover here?