1. A computer-implemented method for analyzing circuit performance variations, comprising: using a computer, allocating circuit performance variation by weighting individual variation parameters in a model selected via a selection process that progressively increases model computational complexity until the model is measurably successful; summarizing device performance variations by summing all weighted individual variation parameter values corresponding to the devices in a circuit design; ranking the device performance variations; and identifying and outputting at least one influential device according to device performance variation rank order, wherein the selection process comprises: if a number of data samples exceeds a number of mismatch parameters, then selecting and solving a first linear model by least squares, else selecting and solving a second linear model by an orthogonal matching pursuit (OMP) algorithm and determining if the second linear model solution accuracy is sufficient; and if the accuracy of the second linear model solution is insufficient, selecting and solving a third linear model via a mixed method.