Ann: Funds Under Management - December 2021, page-114

if you want to properly compared performance you can’t picked and chose a period you have to go long term the longer the better
and excuse like last 2 years or what ever period is unusual
because market index doesn’t care that the beauty of it and the simplicity of it

you get the good and bad all lump in without excuses whether it pro long down turn or massive market crashes or super bull cycle

people know if they invest in the index they get market index return so if it down 50% or up 50% they accept it no excuses.

just like Warren Buffet example no excuses when market down 37% and some hot shot manager gloat by 14% outperformance
nor the index gloat when they start leaving the fund manager behind