A performance variable with a one-sided specification cannot be measured directly, but one or two related variables (called screening variables) can be measured. The screening variables are used to select product in order to raise the proportion of units within specifications from the proportion 7 in the complete population to a specified higher proportion 5 within specifications after screening. Tabulations are given for the situation where the screening variables and the performance variable are jointly normally distributed with known parameter values with final proportionsδ= 0.95, 0.99 and 0.999 of acceptable product desired.