A method includes testing to failure a plurality of semiconductor test structures, measuring a parameter of each semiconductor test structure after experiencing a failure, and generating a cumulative probability distribution function (CPDF) of cumulative probability versus the measured parameter after failure for the plurality of semiconductor test structures. The method further includes performing simulations for a circuit having an area using a model of a transistor that mimics the failure to determine a parameter threshold value that defines a minimum acceptable performance level of the circuit, determining a cumulative probability value from the CPDF that a transistor will not have the parameter at a level below the parameter threshold value, adjusting a value of the area of the circuit based on the cumulative probability value, and computing a first reliability value based on the adjusted area value.