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Career ratings for: Petersons, Andrejs

  Date of rating  

World Rank Rating +/- Age
06/30/1958#206231570
12/31/1958#222230970
06/30/1959#243231971
12/31/1959#240231671
03/31/1960#264231471
06/30/1960Inactive230781
09/30/1960Inactive230781
12/31/1960Inactive230381
03/31/1961Inactive230881
03/31/1962Inactive231885
03/31/1964#192239261
06/30/1964#192239661
09/30/1964#186239661
12/31/1964#192239761
03/31/1965#221239769
06/30/1965#221239869
09/30/1965#214240069
12/31/1965#207239969
03/31/1966Inactive239179
06/30/1966Inactive239179
09/30/1966Inactive239679
12/31/1966Inactive239379
03/31/1967Inactive237183
06/30/1967Inactive237383
09/30/1967Inactive237683
12/31/1967Inactive237383
03/31/1968#288235568
06/30/1968#296235568
09/30/1968#301235468
12/31/1968#305235568
03/31/1969Inactive235878
06/30/1969Inactive236178
09/30/1969Inactive236178
12/31/1969Inactive236378
02/28/1970Inactive236178
04/30/1970Inactive236489
06/30/1970Inactive236389
08/31/1970Inactive236589
10/31/1970Inactive236789
12/31/1970Inactive236689
02/28/1971Inactive236289

These ratings, calculated for Petersons, Andrejs, 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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