Fig 2. Direct range restriction (DRR): Root mean square error (RMSE) of the estimates of the predictive validity (${\widehat{r}}_{\text{b}}$ and ${\widehat{r}}_{\text{pb}}$).

${\widehat{r}}_{\text{b}}$ is the estimate of the biserial correlation coefficient for an artificially dichotomous criterion variable, and ${\widehat{r}}_{\text{pb}}$ is the estimate of the point-biserial correlation coefficient for a naturally dichotomous criterion variable.