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Career ratings for: Parrella, Alfredo

  Date of rating  

World Rank Rating +/- Age
01/31/1995Inactive220879
02/28/1995Inactive221279
03/31/1995Inactive220979
04/30/1995Inactive221079
05/31/1995Inactive221079
06/30/1995Inactive220779
07/31/1995Inactive220579
08/31/1995#3377220169
09/30/1995#3438219969
10/31/1995#3436220069
11/30/1995#3467219569
12/31/1995#3450220069
01/31/1996#3021224771
02/29/1996#2993225171
03/31/1996#3013225071
04/30/1996#3019224971
05/31/1996#3011224971
06/30/1996#3059224471
07/31/1996#3096224271
08/31/1996#3564220875
09/30/1996#3633220575
10/31/1996#3644220575
11/30/1996#3697220175
12/31/1996#3674220675
01/31/1997Inactive224081
02/28/1997Inactive224381
03/31/1997Inactive224281
04/30/1997Inactive224281
05/31/1997Inactive224181
06/30/1997Inactive223781
07/31/1997Inactive223581
08/31/1997Inactive220186
09/30/1997Inactive219786
10/31/1997Inactive219886
11/30/1997Inactive219386
12/31/1997Inactive219786
01/31/1998Inactive223884
02/28/1998Inactive224284
03/31/1998Inactive224384
04/30/1998Inactive224484
05/31/1998Inactive224484
06/30/1998Inactive223984
07/31/1998Inactive223784
08/31/1998Inactive220388
09/30/1998Inactive220088
10/31/1998Inactive219988
11/30/1998Inactive219588
12/31/1998Inactive219888
01/11/1999Inactive219888
01/18/1999Inactive219888
01/25/1999Inactive219988

These ratings, calculated for Parrella, Alfredo, incorporate all games (against rated opponents) played in the year before the "Date of rating", along with the ratings that were already calculated one year previously. If a player has an insufficient number of games in recent years, there may be gaps in the list, even though you may see ratings listed on previous and/or subsequent dates. Whenever a player has played no rated games for three straight years, or dies, they are removed from the list.

Definition of columns in the above list:

Date of rating is the "effective date" of the rating. The rating calculation does not include any games occurring after the "Date of rating".

World Rank refers to the player's world rank on that date.

Rating is the calculated rating for the player, as of the "Date of Rating". This represents the player's estimated strength on the following day.

+/- is the standard deviation of the player's rating estimate. It is based on a geometric average of the number of rated games played in past years. Players who play very frequently will have a smaller +/- value, indicating a greater confidence in the accuracy of their rating. Players whose +/- value exceeds 76 are classified as "Inactive" due to their infrequent play against rated opponents. Mathematically, a player's rating is an estimate of their exact strength on the day after the "Date of Rating". The +/- value represents the standard deviation of that estimate; the player's true strength on that date should be within one standard deviation of their calculated rating approximately 68% of the time, and within two standard deviations of their calculated rating approximately 95% of the time.

Age is the player's exact age in years, on the "Date of Rating". If a player's age is displayed as a link, that means that this rating was active at the time of their next birthday. Click on the link to see the sorted list of all players' ratings on their birthdays when turning that same age.

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