Running_Man
Thinks s/he gets paid by the post
- Joined
- Sep 25, 2006
- Messages
- 2,844
On the blog a reoccurring view of Bernstein's quote "A wildly optimistic historian might give us another few centuries of economic, political, and military continuity. Back-of-the-envelope, that’s about an 80% survival rate over the next 40 years. Thus, any estimate of long-term financial success greater than about 80% is meaningless." is presented.
This thought has been quoted to imply that 80 percent success rates are equal in survival probability to 100 percent success rates which they surely are not.
This mathematical error has been repeated enough to become integrated into financial planning by apparently the Trinity study. Unless the financial failures calculated were due to economic, political or military continuity which is certainly not the case used in the TRINITY study then that is an additional chance of failure is not a subset of the Bernstein's withdrawl from his mule calculation but a unique seperate calculation.
If you accept the calculation from Bernstein on that part -- the calculation by Trinity is the remainder of the other 80% of which the 75% success yield's a total expected success rate =
( .2 X 0% <Bernstein's rate of non continuity of financial society>) + (.8 X .75% <financial continuity expected success rate>) = 60% success rate for 7% non inflation indexed withdrawals. Therefore to utilize a withdrawal calculation near 100% would actually improve your chances of not going bust in your retirement by 33.33% which is very statistically significant.
This thought has been quoted to imply that 80 percent success rates are equal in survival probability to 100 percent success rates which they surely are not.
This mathematical error has been repeated enough to become integrated into financial planning by apparently the Trinity study. Unless the financial failures calculated were due to economic, political or military continuity which is certainly not the case used in the TRINITY study then that is an additional chance of failure is not a subset of the Bernstein's withdrawl from his mule calculation but a unique seperate calculation.
If you accept the calculation from Bernstein on that part -- the calculation by Trinity is the remainder of the other 80% of which the 75% success yield's a total expected success rate =
( .2 X 0% <Bernstein's rate of non continuity of financial society>) + (.8 X .75% <financial continuity expected success rate>) = 60% success rate for 7% non inflation indexed withdrawals. Therefore to utilize a withdrawal calculation near 100% would actually improve your chances of not going bust in your retirement by 33.33% which is very statistically significant.