The cut, or critical, score is determined by those values in the sampling distribution that represent the beginning of the region of rejection. It is at this point on the distribution that, if the level is exceeded, the null hypothesis is rejected. Cutoff scores also are used in regression discontinuity designs. In this type of design, the experimenter assigns units to condition on the basis of a cut score. The assignment variable can be any measure taken prior to treatment in which the units scoring on one side of the cut score are assigned to the treatment group and those on the other side to the control group.