2.6.1 The Problem of Time Dependence.

If you make a rating you are in a dilemma:

• Game results are very coarse type of data (See section 2.5 Game Results are Coarse Data..). Either one or the other player wins. Draws are rare.

• The strengths of players change with time. This is especially true for young players and for beginners.

In order to get a less noisy and more reliable estimate of the rating, we could accumulate more games for the calculation (See section 2.5.2 How Precise is my Rating?.). But considering the mean value is pointless if the rating changes. Therefore we must find a compromise between the two goals noise suppression and timely correct ratings.

The problem is not caused by a special rating method; it is inherent in the rating itself.