Ageing Factor (6)
Following on from an earlier question I thought it would be a useful reference to document how players age with regard to their Ageing Factor.
The decrease is non-linear, and I believe that there are 4 separate stages that each have a different rate of decline.
1. The Ageing Factor remains constant at 100% up until the age of around 21 years 18 weeks.
2. From 21y18w it declines at a rate of 1% every 30 weeks until the age of around 26 years (possibly a little earlier).
3. From age 26 to 30 it declines at a rate of 1% every 21-22 weeks.
4. From age 30 onwards it declines at a rate of 1% every 12-13 weeks, which is roughly 4% per year. This is why outfield players drop off quite quickly once they reach 30 years of age.
Since the reported Age Factor is a rounded value, how do you know exactly what value to use if you're doing a calculation? So here is a quick reference that will give a more accurate percentage:
The correct formula has now been posted below, but this table may still be useful as a quick reference. I have also amended any minor errors.
Age Factor - Age
- 100% - 21y18w
- 99.00% - 21y48w
- 98.00% - 22y26w
- 97.00% - 23y04w
- 96.00% - 23y34w
- 95.00% - 24y12w
- 94.00% - 24y42w
- 93.00% - 25y20w
- 92.03% - 25y49w
- 91.69% - 25y50w
- 91.00% - 26y13w
- 89.98% - 26y35w
- 89.02% - 27y04w
- 88.00% - 27y26w
- 86.98% - 27y48w
- 86.02% - 28y17w
- 85.00% - 28y39w
- 83.98% - 29y09w
- 83.02% - 29y30w
- 82.05% - 29y51w
- 82.20% - 30y00w
- 82.04% - 30y02w
- 81.00% - 30y15w
- 80.04% - 30y27w
- 79.00% - 30y40w
- 78.04% - 31y00w
- 77.00% - 31y13w
- 76.04% - 31y25w
- 75.00% - 31y38w
- 74.04% - 31y50w
- 73.00% - 32y11w
- 72.04% - 32y23w
- 71.00% - 32y36w
- 70.04% - 32y48w
For other values use the formula below.
The problem is that he couldn't get the actual values, there are some 0.0X difference with his method.
Good shout! I'll also see if I can produce a formula at some point.
So, I've finally managed to produce what I believe is the correct formula for the Ageing Factor.
1. The Ageing Factor remains constant at 100% up until the age of 21 years 18 weeks.
2. Starting at 21y19w it declines at a rate of 1% every 30 weeks until the age of 25 years 49 weeks. Which is 1.7333% per season.
- AF = 1 - 0.001*(x/3) = where x is age in weeks greater than 21y18w
3. There is a noncontiguous change at age 25y50w, when the players ages by the equivalent of about 10 weeks.
4. From age 25y50w the AF declines at a rate of 3% every 65 weeks, which is 0.6% every 13 weeks, 0.0461538% per week, or 2.40% per season. This continues until the age of 29 years 51 weeks.
- AF = 0.916 - 0.03*(y/65) - where y is age in weeks greater than 26y00w
(Formula is based on 91.6% at age 26y00w for simplicity. Also use with the previous 2 weeks where the increment becomes positive.)
5. There is a further noncontiguous change at age 30 years 0 weeks, where the player gets younger by the equivalent of 3-4 weeks. Yes, younger!
6. From age 30 until 47 years 18 weeks the AF declines from 82.2% at a rate of 2% every 25 weeks, which is 0.08% per week and 4.16% per season.
- AF = 0.822 - 0.0008*z - where z is age in weeks greater than 30y00w
7. The Ageing Factor remains constant at 10.0% from the age of 47 years 19 weeks onwards.
(Eddie's formula, mentioned above, is very close but is not 100% accurate.)
I want to acknowledge the contribution of Sazz, who helped provide me with data for analysis.
Finally, what took you so long :)