In scrabble, how does the Elo rating system work?

ELO is a system that can rate any game or competition. It is necessary to start with a fixed rating. If you win a game, your rating climbs up – the tougher your opponent, the higher your rewarding rating points.
On the other hand, if you lose a game, your rating drops down – the weaker your opponent, the more points you lose. Also, the difference between your potential gain and loss is fixed at 20 rating points. This means that you can go up against a more challenging opponent and win 16 points, but you’ll lose 4 points if you lose that exact match.