Lithographic improvements obtained from process modifications or application of optical enhancement techniques can often be obscured within experimental noise and inconsistent data analysis techniques. At IBM, the need for a common platform for the accurate analysis of lithographic data led to the development of a new software analysis package entitled LEOPOLD. In this article, the exposure-defocus methodology taken by LEOPOLD for accurate calculation of the total lithographic process window in the presence of experimental noise is outlined; the extension of this method to the evaluation of the common process window through applications in the areas of optical proximity effects, analysis of optical enhancement techniques, and across-field exposure tool characterization is also demonstrated.