Symbolism, Imagery, Allegory
Ah, the leader board—all the guys need to get on it, and all the guys want to be on top. Throughout the play, the leader board comes to symbolize dominance and even manhood (at least manhood as these gentlemen perceive it), and being on top allows you to command the room and all those around you. This is what Moss says to Roma before Moss hightails it out of the office:
MOSS: You're hot, so you think you're the ruler of this place…?! (2.1.382-383)
As angry as this makes Moss, Roma does come off as a sort of ruler of the office, with others often deferring to him and Williamson giving him preferential treatment. This isn't necessarily because anyone actually likes Roma, but rather because he's on top of the leader board. He's the "man" among men—the alpha dog.
The thing about the leader board that's perhaps most interesting when we think about this play as a critique of the American Dream, though, is that striving for the top ultimately brings about Levene's ruin. Another way to think about this is that by placing a premium on dominance and manhood, everything can be lost.