Sharpe ratio
Average return divided by the standard deviation of returns; a measure of return per unit of volatility.
The Sharpe ratio scales a strategy’s average return by how much its returns bounce around, so two strategies with the same average result rank differently if one is steadier than the other.
It assumes returns are roughly symmetric, which a grid or martingale strategy’s returns rarely are: many small gains and one rare large loss can still produce a Sharpe ratio that looks strong right up until the large loss happens.