It's not just the size of your word that counts...
Though most of us are looking for a big, high scoring word to show off our vocabulary and impress our friends, there is more to winning at scrabble than just playing the longest, or even the highest scoring word possible. At higher levels such as competition play, good strategy makes all the difference.
For many of our users, "strategy" may mean picking a word which is plausible enough to not look like cheating. Fair enough, but to us, strategy means picking a word which will lead to the best chance of winning the game.
We do this by using various analytical methods to examine properties of each move, such as how your opponent(s) may able to respond, the quality of tiles you will be left with for your next move, how much it scores, and other such attributes. We also change the strategy as the game progresses and use different strategies for different dictionaries. The result is that we give each move a value according to how well it faired in these tests, and show this value in brackets alongside the score. Although we do attempt to gauge the opponent's response, we don't run deep simulations to examine how the game might unfold which means we may miss the odd trick. This is simply because it takes several seconds to run the simulations to a meaningful depth and doing that for everyone would melt our servers.
You can pick whether to order your results by value or score, and can save this preference in your profile so that it is remembered. Playing the most strategic move (i.e. the one with the highest strategic value) will give on average a 70-75% win rate over someone playing the highest scoring move!
The strategy evaluator is currently only available for English and French dictionaries.
Towards the end of the game, the solver starts to use the fact that it knows with greater certainty what tiles are left in the bag. It is assumed you are playing against one opponent, and their rack will be factored into the unseen tiles. You can however change the opponent count if you are playing against more opponents.