For many, industry standards like Sharpe Ratio, Sterling Ratio and Sortino Ratio come to mind. Although, it is my opinion that these ratios represent more hindsight than foresight.
Take, for example, the S&P option writing programs of the early to mid 2000’s. One of the best known was ACE Investment Strategies. ACE had performance ratios off the charts (Sharpe, Sterling, Sortino, MAR) with smooth, consistent growth and barely noticeable drawdowns. From just about any measure, investors could not have asked for more. It was the darling of retail brokerage firms with small minimum account size requirements. (See graph below)

But, just like Long Term Capital Management, Ace had a sudden and for most, unexpected implosion! After years of flawless growth, they had close to a 70% drawdown in several months! (see graph below)

In hindsight, ratios such as Sharpe were worthless. They lured many people into the lion’s den!
But, there was one group of risk analysts who did have an excellent handle on the potential for Ace’s implosion. Who was it? The Chicago Mercantile Exchange, that is who.
It was the CME that set the margin requirements, and Ace was trading at high margin to equity ratios of 50% and more. This compares to many CTAs who trade at less than 20% and some less than 10% margin to equity ratios.
It is my opinion that margin usage is a leading indicator of potential risk and drawdowns, but there is one school of thought that thinks using more margin is not necessarily dangerous because it can add to diversification. To some degree I agree with this, but traders quickly reach a point of diminishing returns.
In the following graph, I have plotted average margin usage against average drawdowns for several hundred CTAs.

Traders can clearly see from the data and trend line that using more margin on average leads to higher drawdowns.
Some investors might say this is obvious, more leverage = more risk, but here on this forum I had a debate with someone who referred to himself as a “mathematical geniusâ€