Systematic Departures from the Frontier: A Framework for the Analysis of Firm Inefficiency
提出将生产或成本前沿的偏离分解为系统性因素和随机成分，并建立无效率误差项模型，利用电力企业数据验证了同时包含系统性和随机成分的优越性。
Departures from a production or cost frontier may reflect the systematic effect of conditions that contribute to inefficiency. To test whether some portion of frontier function departures can be systematically explained, the frontier inefficiency error component is modeled as a function of various causal factors and a random component. The functional form of the inefficiency error term model is chosen to assure strict one-sidedness. Preliminary empirical results generated from electric utility data suggest the superiority of including both systematic and random components in the inefficiency error term.