How do you calculate E-Ratio?

Record Maximum Favorable Excursion (MFE) and Maximum Adverse Excursion (MAE) at each bar since signal entry. Normalize both by ATR. Average all normalized MFE and MAE values at each time step. Divide average normalized MFE by average normalized MAE at each bar to get E-Ratio over time.

What is a good E-Ratio value?

An E-Ratio above 1.0 means the trade moves more in your favor than against you. A value of 1.2 means 0.2 additional units of volatility in your favor. Higher is better. Critically, your strategy's E-Ratio (blue line) should also be above the random baseline (red line) to confirm the edge isn't attributable to chance.

How can E-Ratio help determine hold time?

If E-Ratio peaks at bar 6 and then falls off a cliff, it probably doesn't make sense to hold for 15 bars. E-Ratio shows when your trading edge decays over time, helping you set optimal exit timing.

Can I use E-Ratio as a fitness function in Build Alpha?

Yes. Build Alpha supports E-Ratio as a fitness function, meaning you can generate strategies that optimize for maximum edge ratio rather than just profit or Sharpe ratio.

What is the random baseline (red line) in E-Ratio?

Build Alpha creates random trading signals and calculates their E-Ratio on the same market data. This random E-Ratio serves as a baseline. If your strategy's E-Ratio cannot beat the random baseline, the edge may not be statistically meaningful.

E-Ratio (Edge Ratio). How to Quantify Trading Edge

Q: What is E-Ratio (Edge Ratio)?

E-Ratio measures how much a trade goes in your favor vs. how much it goes against you at each time step after entry. It's normalized for volatility using ATR, which allows comparison across all markets and regimes. A value above 1 means more favorable movement than adverse movement.

What Is E-Ratio (Edge Ratio)?

Edge Ratio or E-Ratio measures how much a trade goes in your favor vs. how much a trade goes against you. It's calculated at each time step after a signal fires, giving you a dynamic picture of how your trading edge evolves over time.

Measurements are normalized for volatility using ATR (Average True Range). This is critical. It allows us to use E-Ratio across all markets and regimes with a common denominator. Once normalized, a value of 1 signifies equal amounts of favorable movement compared to adverse movement.

In other words, the y-axis is an expression of how many units of volatility more (or against) your trade gets. A measure of 1.2 would indicate 0.2 units more of favorable volatility. A measure of 0.8 would indicate 0.2 units more of adverse movement.

E-Ratio (Edge Ratio) chart in Build Alpha showing blue line for strategy signal and red line for random baseline, with x-axis as bars since signal and y-axis as edge measurement

E-Ratio chart: blue line = your strategy's edge over time. Red line = random baseline. X-axis = bars since signal. Y-axis = volatility-normalized edge.

How to Read the E-Ratio Chart

The blue line is your selected strategy's signal. The red line is the E-Ratio for a "random" strategy on the same market. It serves as a baseline to beat.

Ideally, you want to see a blue line above 1 and above the random line. You may find many "good" strategies, but if they have an E-Ratio less than the red baseline or less than 1, we should be less confident that the trading signal will withstand the test of time.

> 1.0

Above 1.0 and above red line: More favorable movement than adverse. The signal demonstrates real edge beyond what randomness would produce.

≈ 1.0

Around 1.0: Equal favorable and adverse movement. No meaningful edge, the signal is essentially a coin flip at this time step.

< 1.0

Below 1.0 or below red line: More adverse movement than favorable. The signal may be harmful, or at minimum, doesn't outperform random chance.

How to Calculate E-Ratio

Record MFE and MAE. At each time step (bar) since your entry signal, record the Maximum Favorable Excursion (MFE) and Maximum Adverse Excursion (MAE). MFE is the best the trade got; MAE is the worst.

Normalize for volatility. Divide each MFE and MAE by ATR at the time of the signal. To compare across markets we need a common denominator, ATR (a unit of volatility) is that denominator.

Average across all signals. You should now have average MFE and average MAE at 1 bar since signal, average MFE and average MAE at 2 bars since signal, and so on.

Divide Average MFE by Average MAE. At each time step. This gives E-Ratio over time, plotted as the blue line in the chart.

Worked Example: E-Ratio at Bar 1

Calculate E-Ratio at one bar out from signal

Signal 1: MFE = 1.50, ATR = 1.27, MAE = 1.00

Signal 2: MFE = 1.33, ATR = 1.19, MAE = 1.04

Signal 3: MFE = 1.83, ATR = 1.67, MAE = 1.27

Average MFE = ((1.50/1.27) + (1.33/1.19) + (1.83/1.67)) / 3 = 1.13 Average MAE = ((1.00/1.27) + (1.04/1.19) + (1.27/1.67)) / 3 = 0.81E-Ratio at Bar 1 = 1.13 / 0.81 = 1.395

So in this example, one bar after our signal, we can expect ~0.40 more units of volatility in our favor than against us. If ATR is 20 points, then we can expect the trade to move on average 8 points (8/20 = 0.4) more in our favor than against us 1 bar after the signal fires.

Interpreting E-Ratio Values

E-Ratio gives you a volatility-normalized measure of edge that you can compare across any market, any timeframe, and any regime. In the example above, an E-Ratio of 1.395 at bar 1 means we get about 0.4 units of volatility more in our favor than against us. That's real, quantified edge.

More capital should go toward stronger edges than weaker ones. However, weaker edges can be combined via ensemble methods and portfolio construction to potentially create stronger ones. E-Ratio presents one way to rank your trading strategies for capital allocation decisions.

Using E-Ratio to Optimize Hold Time

One of the most practical uses of E-Ratio is determining when your edge decays. If E-Ratio falls off a cliff at bar 6, then it probably does not make sense to hold for 15 bars! You don't want to be holding a trade when the edge starts to dissipate.

E-Ratio peaks around bar 6, marking the point where edge is strongest before it begins to decline.

In the chart above, we can clearly see the most edge around bar 6 where the E-Ratio peaks at about 1.6, meaning 0.6 more units of volatility in our favor than against us. After that point, edge begins to decline. This tells us the optimal exit window and helps set stop-loss and profit-target levels based on when the signal's predictive power is strongest.

The Random Baseline (Red Line)

Build Alpha creates random trading signals and calculates their E-Ratio on the same market data. This random E-Ratio serves as a baseline, the red line in the chart. If your strategy's E-Ratio (blue line) cannot beat the random baseline, the edge may not be statistically meaningful.

Specifically, Build Alpha creates a random signal and random set of price data for each signal the user selects. If you run a simulation using 373 signals, Build Alpha creates 373 random trading signals. It then attempts to create the best possible strategy using those random signals. The best "random" strategy serves as a benchmark, creating more random signals as you select more real signals makes it harder for your strategies to beat this benchmark. This is closely related to the Vs Random Test in Build Alpha's robustness suite.

E-Ratio as a Fitness Function

Build Alpha supports E-Ratio as a fitness function, meaning you can generate automatically generated trading strategies that optimize for maximum edge ratio rather than just profit, Sharpe ratio, or other traditional metrics.

Why would you want to do this? Optimizing for E-Ratio tends to produce strategies with cleaner, more consistent edge profiles, signals where the favorable-to-adverse movement ratio is genuinely strong, not just the result of a few lucky outlier trades inflating the P&L. Strategies with high E-Ratios often have better resistance to curve fitting because the edge is broad-based rather than dependent on specific price paths.

Practical Applications

Rank & Compare Strategies

Use E-Ratio to rank strategies by the strength of their edge. Allocate more capital to strategies with higher E-Ratios.

Optimize Exit Timing

Identify when edge peaks and decays. Set hold times, stops, and targets based on the E-Ratio curve's shape.

Cross-Market Comparison

Because E-Ratio is volatility-normalized, compare the same signal's edge across gold, S&P 500, bonds, forex, all on the same scale.

Validate Signal Quality

If a signal looks profitable but has an E-Ratio below the random baseline, the profits may be noise. E-Ratio separates real edge from luck.

Improve Signals with Triggers

Adding a trigger signal can dramatically improve E-Ratio. One test showed a 36% improvement from adding a trigger to a main signal.

Portfolio Allocation

Stronger E-Ratio strategies get larger allocations. Weaker ones can be combined in portfolios where their ensemble may produce stronger combined edge.

E-Ratio in Build Alpha

Build Alpha calculates E-Ratio automatically for every strategy it generates. You can view the E-Ratio chart in the strategy results window, use E-Ratio as a fitness function for strategy generation, and compare your signal's edge against the random baseline, all with no coding required.

E-Ratio is one of many ways Build Alpha helps you visualize and quantify edge. Others include Monte Carlo distributions, equity curves, heat maps, and the full suite of robustness tests. Together, these tools ensure that what you're deploying to live markets has real, measurable, statistically significant edge.

I spoke quite a bit about E-Ratio in a podcast interview with Andrew at BetterSystemTrader.com/79, please check it out.

Thanks for reading,
David

Updated February 2026.