Given this statement.... "Position size must be calculated based upon market volatility and assigned per position risk" The statement and many like it have been published by "successful" or seemingly sucessful trend following organizations and individuals. My question is how? Does greater volatility when a position is entered mean that one should decrease size or increase size? If my methodology is following a daily chart, do I consider some relationship with daily volatility or rather weekly or monthly? If I get a signal during relatively low volatility, alerting me to a possible breakout is it more advantagous to add to these positions? I don't want to debate the statement here, just try to better understand assuming that it is an accurate statement. I realize the answers are unique to the individual trading methodology, but what are other traders here doing that is successful in relation to position sizing, risk and market volatility.