BBO skill is a very poor way of rating players. First of all your score on BBO is compared to 15 other pairs, which is hilarious knowing the amount of players online every day. In comparison: OKbridge compared 52 pairs AND did not count the top 2 and bottom 2 scores for the average to compare with. On BBO scores for one board mean next to nothing since players frequently don't finish a board, since they play only a few cards to move on to a team game or a tourney (this happens at least 10 times a day at my table), then the board is finished by a new player who has no clue about the play before, or it gets claimed. Often angry players bid 7NT in rage and redouble, then leave, or stay and claim. Or claim down 10 in a board which is only down 1 or 2. On BBO there are many pick up partnerships with none or very few agreements, lots of boards get ruined because of lack of agreements (3 misunderstandings per board is not uncommon). Then there are the players who just start to play bridge and rate themselves expert or better, you play with them, get a few terrible scores, stop playing, meanwhile BBO skill thinks you are a beginner. BBO skill uses only PART of these really silly scores, ONLY the previous month. So if you don't play a month, or just a few boards, your rating drops dramatically. BBO skill should go where it belongs: in the toilet.