Our sample includes all firms from selected industries (see below) with sufficient Compustat data to estimate industry-specific production-functions in any year of our five-year sample period (1993-1997)[5]. We exclude financial services and other regulated industries, such as transportation and utilities: these regulated industries are likely to have different operating environments (e.g. regulated vs. competitive), which may affect firms’ behavioral goals. The remaining industry-years represented in the sample are those with sufficient data to estimate the production frontier for that industry-year. At the frontier estimation stage, the data are tested for possible outliers