We'll go over this "study", the National Retirement Risk Index.
https://crr.bc.edu/briefs-financing-retirement/the-national-retirement-risk-index-version-2-0/
Ed McQuarrie talks the REAL History of Stocks and Bond performance.
https://www.morningstar.com/funds/what-doubters-get-wrong-about-6040-portfolio
What the 60 percent stock portfolio and the 40 percent bond portfolio helps your portfolio