As suggested in the question I have taken FIDE rating data from 1992 (when active/inactive flags were first introduced) through to September 2019 taken from Olimpbase and FIDE and loaded it into a database which has allowed me to run SQL queries against the data to get some answers for this question. I looked at average decline in playing strength for players in 5 year age bands from 15 through to 85 and in 100 point playing strength bands from 1500 through to 2700.
I shall present my conclusions from looking at the data first, followed by a brief description of my method followed by the data.
Conclusions
First, I should emphasise that here I am talking about averages. Individuals will obviously vary, possibly wildly from the averages.
- Young, weak players improve faster than older, stronger players.
Players in the two weakest bands, 1500 - 1700, continued to improve
through to their early 30's.
- Mid strength players (1700 - 2200) start declining first, in their
late 20's. At this age weaker players are still improving and
stronger players are maintaining their level.
- Mid strength players decline faster in middle age and early old age
than both weaker and stronger players.
- Weaker players are more variable (have a higher standard deviation)
than stronger players until you get to your 80's when I guess it starts
falling apart for everybody.
- Finally, to answer the question about my prospects. I am in the 60-65
and 1700-1800 band so I can "look forward" to an expected decline of
139 points over the next 10 years with a standard deviation of 118.
Of course I expect this not to happen. I blame my current low rating
on getting "mugged" by several very under-rated juniors last year and
I promise I will study more (fingers crossed behind my back).
Method
For each age and rating band I selected the average rating decline over a 10 year period and the standard deviation for each player in the band who was active at the beginning and end of the 10 year period. I restricted these calculations to where I had at least 50 data points, hence the gaps in the following data for older age groups. I ran this query over all the data in the database.
For each age/rating point there are two numbers. The first is the average decline. If this is a negative number it indicates an average increase in rating. The second number, in brackets, is the standard deviation. For a normal distribution 95% of the results would fall within a range of +/- 2 standard deviations. However average improvement/decline is almost certainly not normally distributed. Nevertheless this figure gives a useful indication of variability.
For instance, the first data point for the 15-20 age band and the 1500-1600 rating band is -161 (174). This means that the average rating increase over a 10 year period for players in this band is 161 points and the standard deviation is 174. This high standard deviation indicates that some players will be improving by several times as much as the average while some may stay roughly the same or even decline.
Compare this with the figures for the 50-55 age band and 2600-2700 rating band. The average decline is 43 and the standard deviation is only 28. This suggests that most, if not all the players in this band are declining slightly in rating.
Results
AgeBand = 15-20
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
-161 (174) -137 (169) -123 (152) -99 (141) -87 (132) -84 (118) -94 (112) -94 (107) -94 (9) -103 (8) -101 (65) -93 (47)
AgeBand = 20-25
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
-89 (158) -58 (151) -34 (130) -28 (123) -21 (109) -15 (95) -23 (82) -32 (79) -30 (76) -35 (64) -35 (55) -28 (52)
AgeBand = 25-30
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
-71 (149) -19 (142) 2 (124) 20 (122) 29 (102) 16 (88) 7 (75) -2 (69) -1 (65) -4 (55) 0 (51) 1 (40)
AgeBand = 30-35
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
-53 (144) -18 (147) 21 (121) 37 (102) 48 (87) 35 (79) 29 (75) 16 (62) 17 (59) 14 (51) 16 (47) 18 (59)
AgeBand = 35-40
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
3 (125) 22 (123) 41 (116) 58 (100) 63 (93) 51 (79) 44 (69) 30 (60) 29 (56) 25 (47) 25 (48) 33 (38)
AgeBand = 40-45
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
25 (113) 22 (110) 70 (120) 73 (108) 80 (91) 66 (78) 57 (68) 42 (61) 38 (57) 35 (51) 38 (44) 38 (37)
AgeBand = 45-50
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
22 (135) 54 (121) 73 (111) 93 (100) 91 (93) 80 (80) 69 (70) 54 (66) 48 (57) 41 (51) 38 (43) 49 (34)
AgeBand = 50-55
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
23 (123) 85 (116) 91 (120) 106 (99) 109 (89) 95 (82) 81 (73) 66 (70) 57 (63) 53 (57) 43 (40) 43 (28)
AgeBand = 55-60
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
66 (127) 84 (103) 117 (106) 129 (106) 126 (103) 108 (89) 92 (76) 73 (72) 70 (67) 54 (54) 55 (47) 44 (38)
AgeBand = 60-65
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
93 (123) 123 (126) 139 (118) 146 (106) 136 (95) 117 (90) 105 (78) 87 (76) 82 (79) 70 (72) 93 (77)
AgeBand = 65-70
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500 - 2600
96 (111) 123 (122) 144 (120) 141 (107) 152 (102) 124 (89) 112 (80) 108 (87) 91 (82) 81 (81) 69 (37)
AgeBand = 70-75
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400 - 2500
96 (115) 119 (131) 147 (128) 153 (124) 161 (104) 135 (93) 125 (84) 115 (91) 93 (74) 63 (65)
AgeBand = 75-80
1500 - 1600 - 1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300 - 2400
119 (207) 156 (180) 171 (123) 167 (141) 173 (101) 156 (101) 138 (94) 126 (96) 134 (92)
AgeBand = 80-85
1700 - 1800 - 1900 - 2000 - 2100 - 2200 - 2300
75 (167) 148 (186) 156 (169) 179 (102) 177 (118) 92 (174)