I keep running into two backtests that both report the same maximum drawdown, say roughly twenty percent, and every instinct I have says treat them as equally risky. They are not. One of them dug a fast hole and climbed out in a few weeks. The other bled slowly, sat underwater for the better part of a year, and clawed back the last stretch so gradually you could have watched paint dry faster. Max drawdown, being a single worst-case number, cannot tell those two apart. That is the whole problem with leaning on it.
The thing max drawdown misses is time. A drawdown is not a moment, it is a stretch. Depth is one dimension, but duration is the one that actually decides whether you keep the position on. Nobody abandons a system because it dropped fifteen percent for a week. People abandon systems because they spent eight months staring at a red number and quietly decided the edge was gone. The metrics below are the ones I actually look at when I want to know how painful an equity curve was to hold, not just how deep it went.
The Ulcer Index, because depth alone lies to you
The Ulcer Index is my favorite of the bunch because it was built around exactly the right question. It measures both how deep drawdowns get and how long they last, and it does it by punishing long, deep underwater periods far more than brief dips. The name is on the nose. It is meant to approximate the stress of holding.
The mechanics are simple enough to compute in a spreadsheet. For each point in your equity curve, calculate the percentage drawdown from the highest peak reached so far. Square each of those drawdown percentages, average the squared values across the whole period, then take the square root. That is the Ulcer Index. Squaring is the trick. It means a curve that spends a long time deeply underwater gets a much higher score than one that dips briefly and recovers, even if both touched the same low point.
Because it squares the drawdowns, a curve at a peak contributes zero, and a curve stuck at negative ten for months contributes a great deal more than a single spike to negative ten. A lower Ulcer Index is better. There is no universal magic threshold, since it depends on the asset and timeframe, but the useful move is to compute it for a benchmark you already understand, like buy-and-hold on the same instrument, and compare. If your strategy has a higher Ulcer Index than just holding the underlying, you are taking on more sustained pain for whatever return you got.
Calmar and MAR, return per unit of pain
Sharpe divides return by volatility, which treats an upside spike and a downside crash as equally bad. Most traders do not actually mind upside volatility. The Calmar ratio fixes that by dividing return by drawdown instead. Specifically, it is the compound annual return divided by the absolute value of the maximum drawdown, typically computed over a trailing window of around three years.
So a strategy returning roughly twenty percent a year with a twenty percent max drawdown has a Calmar of about one. That is a reasonable rough anchor. Below one and you are earning less per year than your worst dip cost you, which is a hard thing to sit through. A Calmar comfortably above one starts to feel like a system you could actually stick with. The MAR ratio is the same idea, return over max drawdown, usually computed over the entire track record rather than a fixed window. People use the terms almost interchangeably, and the distinction that matters is just which period you measured over, so always ask.
The catch with both is that they hang everything on a single number, the max drawdown, which is one observation and can be an outlier. A strategy can have a lovely Calmar right up until the one drawdown that was not in the sample shows up. Treat Calmar as a summary, not a guarantee.
Recovery factor and time underwater
Recovery factor is net profit divided by max drawdown. It answers a blunt question. For every unit of drawdown pain you endured, how much total profit did the strategy actually produce over its life. A recovery factor near one means the strategy made about as much as its worst drawdown cost, which is thin. Higher is better, and the number tells you whether the whole endeavor was worth the deepest hole it dug.
The metric I would not skip is the plainest one, and hardly anyone reports it. Time underwater, sometimes called the maximum drawdown duration, is simply the longest stretch between an equity peak and the moment the curve got back to that peak. Not the depth. The number of days, weeks, or months you spent below a prior high. This is the metric that most closely predicts whether a human abandons a strategy, because conviction erodes with time far more reliably than with depth.
Here is the practical workflow I run on any equity curve before trusting it:
- Compute max drawdown for the headline, then immediately ignore it as your only input.
- Compute the Ulcer Index and compare it against buy-and-hold on the same instrument over the same window.
- Compute Calmar or MAR and be clear about which trailing window you used.
- Find the longest time-underwater stretch and ask honestly whether you would have held through it without touching anything.
- Check recovery factor to confirm the total profit justified the deepest hole.
The failure mode I have watched most often is someone picking a strategy on Sharpe and max drawdown alone, going live, and quitting four months into a recovery that would have completed in six. The backtest was fine. The trader could not sit through the time underwater because nobody had shown them how long it was going to be. A high Ulcer Index or a long max drawdown duration in the backtest is your advance warning of exactly that, and it is a warning worth heeding before you commit real size.
None of these replace judgment, and none of them are hard to compute. If I could keep only two, I would keep the Ulcer Index and time underwater, because between them they capture the shape of the suffering, which is the part that actually determines whether you are still holding the position when the recovery finally arrives.