WILLIAM BENGEN’S SEMINAL STUDY in the October 1994 Journal of Financial Planning, “Determining Withdrawal Rates Using Historical Data,” helped usher in the modern era of retirement withdrawal rate research by codifying the importance of sequence of returns risk. The problem he set up is simple: A new retiree makes plans for withdrawing some inflation-adjusted amount from his or her savings at the end of each year for a 30-year retirement period.
Pfau, Wade D., "Ten Reasons Why the 4 Percent Rule Is Too Simplistic" (2014). Faculty Publications. 366.