Pain index and pain ratio: drawdown-time integrated risk measures
Maximum drawdown captures the depth of a portfolio's worst loss but says nothing about how long the loss persisted. A 30% drawdown that recovered in six months is a different experience from a 30% drawdown that took five years to claw back. The pain index captures both dimensions in a single statistic; the pain ratio combines it with the return to produce a Calmar-style risk-adjusted measure.
What the pain index and pain ratio are
The pain index, developed by Thomas Becker, is the average depth of the drawdown time series over an evaluation period. For each observation in the series, the value is the drawdown from the running peak; the pain index is the simple average of these values. The metric integrates both depth (how far below peak the portfolio fell) and duration (how long it stayed there): a portfolio that spent five years 20% below peak will have a pain index of approximately 20% even if no single drawdown reading exceeded that figure.
The pain ratio is the analogue of the Calmar ratio with the pain index in the denominator. It is defined as the compound annual return divided by the pain index: pain ratio = CAGR / pain index. As with Calmar and Sterling, higher is better, and the metric is unitless and scale-free.
How it works
Consider two strategies with the same CAGR (say 8%) and the same maximum drawdown (say −30%). Strategy A reaches the −30% trough briefly and recovers within a year; the rest of the time it is near peak. Strategy B reaches the same trough and remains 25% below peak for four more years before recovering. Both have the same Calmar ratio (8 / 30 = 0.27). The pain index of A is much smaller than that of B because the average drawdown observation across the series is smaller; the pain ratio of A is correspondingly higher than that of B. The metric distinguishes the two experiences in a way that maximum drawdown alone cannot.
Computing the pain index requires the full drawdown time series. For each date t, drawdown(t) = price(t) / max(price(s), s ≤ t) − 1, expressed as a non-positive number. The pain index is the absolute value of the simple average of drawdown(t) across all dates in the evaluation window. The metric is bounded between 0 (a portfolio that never falls below peak) and the magnitude of the maximum drawdown (a portfolio that immediately falls and never recovers).
What the evidence shows
Across diversified equity portfolios over multi-decade evaluation windows, the pain index typically lies in the 5–15% range and the pain ratio in the 0.4–1.0 range. Equity drawdowns of 30–50% in the worst episodes (1929–1932, 2000–2002, 2007–2009) are responsible for a disproportionate share of the integrated pain, because the recovery period from those drawdowns extended over multiple years.
The pain index also distinguishes strategies with the same maximum drawdown but different recovery profiles. Trend-following CTA strategies, which historically have shorter drawdown durations than buy-and-hold equity, tend to score better on pain ratio than on Calmar relative to a buy-and-hold equivalent. The metric is therefore particularly informative for evaluating strategies whose value to an investor depends on how quickly they recover, not just how deeply they fall.
Becker's original work and subsequent refinement have established the metric as a standard reporting figure in some hedge-fund and managed-futures contexts, although it is less universally adopted than Sharpe or Calmar.
Limitations and trade-offs
The pain index requires the full drawdown time series, which means the value depends on the sampling frequency. A daily series produces a different pain index from a monthly series for the same underlying strategy, even after annualisation. Comparisons across strategies should use a consistent sampling frequency.
Because the metric integrates over the entire evaluation window, it gives equal weight to all drawdown observations regardless of how distant they are. A bad year fifteen years ago contributes the same to the pain index as a bad year last year. Investors who are more concerned about recent drawdown experience may prefer rolling-window pain indices over the full-history version.
Like all drawdown-based metrics, the pain index assumes the return series is continuous and that prices are observable in unbroken sequence. Illiquid assets that are not marked to market—private equity, illiquid credit—will show artificially low pain indices because the drawdown time series is incomplete. The metric is most informative for liquid, exchange-traded assets and portfolios.
Pain index and pain ratio in pfolio
The pain index and pain ratio are not currently displayed in pfolio Insights. The drawdown time series, maximum drawdown, time underwater, and CAGR are available; pain-based metrics can be calculated externally from the drawdown series.
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