# chess.com

## How do the score and ratings work in Lessons?

Lessons use a sophisticated scoring and rating system to track your overall performance, as well as your strengths and weaknesses in different aspects of the game.

For each Lesson you are given a score based on performance. This score is out of 100 possible points. Points are deducted for using hints and other help tools, for taking time, and for incorrect move attempts.

The philosophy is that it is much better for you to thoughtfully discover the solution for yourself using hints, than it is to "stumble upon" the solution by making haphazard guesses.

ACTION IMPACT
Make ALTERNATIVE MOVE 0%
Show DIFFICULTY -0% of TOTAL
Show MATERIAL BALANCE -0% of TOTAL
Show TOTAL STEPS/MOVES -2% of TOTAL
1 min of TIME -1% of MOVE
Show SUBTLE HINT -2% of MOVE
Show GOAL -1% of TOTAL
Show STRONG HINT -6% of MOVE
Show DIRECT HINT -10% of MOVE
Show ANALYSIS BOARD -4% of MOVE
Show KEY PIECES -10% of MOVE
Show KEY SQUARES -15% of MOVE
Show CORRECT PIECE -24% of MOVE
Show CORRECT SQUARE -30% of MOVE
Make WRONG MOVE -30% of MOVE
Show ANSWER -100% of MOVE

The score is calculated using the following method: Each lesson has a given number of moves. Each move is given a "relative importance" from 1 to 10 which sum up to the total possible points. Then, each time you do certain things like look at hints or make wrong moves, you lose a percentage of these points. The table below shows the different actions and their associated impact.

For example, if you have a lesson that has two moves in it, the first having a move importance of 5, and the second with a move importance of 10, you have 15 total possible points.

Let's say that on move 1 you use a STRONG HINT (-10%) and a SHOW KEY PIECES (-10%). Then we get (5 -10% -10%) = 4. Then on the second move we take 2 extra minutes of time (-5% each) and the analysis board (-15%). We then get (10 -5% -5% -15%) = 7.5. Add them together and we get 11.5 out of 15 points, or 77% out of 100% on the lesson. That is how the score is calculated.

The rating is calculated by taking the rating of the lesson and then plugging in your score (in this case 77%) to the Glicko formula to get your new rating. In chess a win is usually worth 1 point, a draw .5 points, and a loss 0 points. But with Lessons your score can be anywhere from 0.0 to 1.0, and your rating is adjusted accordingly. You then receive a new rating, as does the lesson!

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