I bleed maroon said:
And my choices (neither right or wrong), for the record:
- Withdrawal rate of 4% (99%+ successful at achieving the stated objective of not running out of money in retirement)
- Rate of Return of 8% (back-tested 50/50 stock/bond portfolio, which I think is appropriate for most retirees, produces 8.22% over time. Note: I would use utilities and blue chip dividend stocks for part of the bond allocation, as bonds are not without risk, either).
- Inflation Rate of 3% (which makes your net return somewhere around 5%)
One of us is argumentative..that's for sure. All I said was 10% equity and 6% bond returns were not conservative, but rather closer to a scenario of lots of up without much down... and I hope that works out for you. So you want a rebuttal...
You mentioned you back tested 10 years. The last 10 years are not a good benchmark for the long-term and the result is largely ignoring volatility. Sticking with that, a BALANCED equity fund over that time averaged +/- 9% and bonds average roughly 2.5%. So, your 10 and 6% returns are not conservative. The S&P index did about 11% over the past 10 years, and 12.5% over the past 15, but it had a 10 year negative return from 2000-2010.
All of these numbers also require a fixed dollar amount at the beginning of the period with no additions or withdrawals in order to achieve those results. I don't the sophistication of the Monte Carlo tool you are using, but the higher the expected return, the higher the std dev that would need to be included in its trials (i.e. wider swings in the sequence of returns). Without adjusting the volatility, then of course, an 8% return with the same assumed volatility as a lower expected return, and only assuming a 4% w/d rate, then of course you will see 99%+ success.
I don't disagree with/argue any of your conclusions. Everything you have said is correct based on your choice of assumptions. However, this thread was a discussion about what return numbers to use for financial planning purposes, and I personally would not feel comfortable banking my future plan success using the numbers you presented.