The Gain-to-Pain Ratio

The Gain-to-Pain Ratio (GPR) is a measure that Jack Schwager introduced in his 1989 book 'Market Wizards.'

The definition is very simple: the sum of returns over all periods (usually monthly), divided by the sum (in absolute value) of the losses in the months that had losses.

For example, if adding up all the monthly returns gives a net return of +40%, and gathering only the losses from the down months gives -20%, then GPR = 40 ÷ 20 = 2.0. It shows 'how many units you earned per unit of pain.'

The reason Schwager created the GPR was that he was unhappy with the Sharpe ratio. The Sharpe ratio uses standard deviation in the denominator, and standard deviation counts even a month that jumped sharply upward (a surge) as 'volatility' and penalizes it.

But a surge isn't something to penalize an investor for, is it? The GPR puts only 'months that had losses' into the denominator (the pain). A month that rose sharply only grows the numerator (the gain) and doesn't enter the pain. So the key difference is that it doesn't treat 'upward jumps' as risk.

The rough interpretive benchmarks Schwager offered are these: a GPR of 1.0 is good, 2.0 is excellent, 3.0 is superb, and 4.0 is world-class. However, he said it's only reliable when viewed with at least 3 years of data.

The GPR's strength is that it's intuitive and easy to calculate. It shows 'how much you earned and how much it hurt' as a single number, so it's easy to understand.

There are cautions too. First, it's sensitive to the measurement frequency. The same asset gives a different value depending on whether you measure it monthly or daily. Second, in a short bull market where there were almost no down months, the denominator is small and the GPR can look unrealistically large. Third, like other risk measures, it doesn't fully capture 'the occasional large drawdown (MDD).'

So the GPR is not all-purpose either—it's one of several measures, to be viewed together with the maximum drawdown and loss duration.