Downside Variance

Downside Variance (or DV) is measured by target semi-variance and is termed downside volatility. It is expressed in percentages and therefore allows for rankings in the same way as variance. One way to view downside volatility is the annualized variance of returns below the target.

Downside Variance  = SUM(RET DEV)2 N(ER)

Downside Variance is the probability-weighted squared below-target returns. The squaring of the below-target returns has the effect of penalizing failures at an exponential rate. This is consistent with observations made on the behavior of individual decision-making under.