I seen a video where it was explained using criteria like location etc. but 2 houses across the street from each other dont necessarily mean they have the best connection. proximity doesnt always mean a better connection. and in MW3 they would search lobbies by ping and it showed that on screen. the video is on this site or was before the move. might have been disabled by the forum change. and ill add Im not referring to "skill based matchmaking" just your normal lobby matching. but maybe the skill based makes a difference even though its not supposed to in public games.