Methods, systems, computer program products and program storage devices for determining whether or not to perform an action based at least partly on an estimated maximum test range. One of the methods comprises: attaining results generated from a parametric test performed on semiconductor devices included in a control set comprising a subset of a population of semiconductor devices; selecting from among the semiconductor devices at least one extreme subset including at least one of a high-scoring subset including all devices whose results exceed a high cut-off point and a low-scoring subset including all devices whose results fall below a low cut-off point; plotting at least results of the at least one extreme subset as a normal probability plot located between a zero probability axis and a one probability axis; fitting a plurality of curves to a plurality of subsets of the results of the at least one extreme subset respectively; extending each of the plurality of curves to the zero probability axis for the low-scoring subset or to the one probability axis for the high scoring subset thereby to define a corresponding plurality of intersection points along the zero or one probability axis; defining an estimated maximum test range based on at least one of the intersection points; and determining whether or not to perform an action based at least partly on the estimated maximum test range.