Finding efficiency regions (ERs) for extremely efficient decision-making units (DMUs) is one of the important issues from the managerial and economic viewpoints. An extremely efficient DMU will remain efficient if and only if after changing its inputs and/or its outputs this DMU stays within its ER. Thus, by applying the ER information, decision maker(s) of the evaluated extremely efficient DMU can precisely understand the values of input(s) increment and output(s) decrement of this DMU so that it remains efficient. Hence, in this study, we propose a data envelopment analysis (DEA) approach based on the defining hyperplanes of the production possibility set (PPS), which is capable of finding the ERs of the DMUs when their inputs increase and/or their outputs decrease. To demonstrate the applicability of the proposed approach, in the real world, a numerical example and an empirical application to the banking industry in the Czech Republic are provided.

中文翻译：

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输入和输出变化的 DEA 效率区域

从管理和经济的角度来看，为极其有效的决策单元 (DMU) 寻找效率区域 (ER) 是重要的问题之一。当且仅当在更改其输入和/或输出之后，该 DMU 保持在其 ER 内时，一个极其高效的 DMU 将保持高效。因此，通过应用 ER 信息，被评估的极高效 DMU 的决策者可以准确地了解该 DMU 的输入增量和输出减量的值，从而使其保持高效。因此，在本研究中，我们提出了一种基于生产可能性集 (PPS) 定义超平面的数据包络分析 (DEA) 方法，该方法能够在 DMU 的投入增加和/或产出减少时找到其 ER . 为了证明所提出的方法在现实世界中的适用性，