非期望产出、影子价格与无效决策单元的改进

Undesirable outputs,shadow prices and improvement on inefficient decision making units

本文首先建立考虑非期望产出的非参数DEA效率模型,从影子价格的视角论证DEA有效的充分必要条件,计算出无效DMU的可改进量,从而构建了一个考虑非期望产出、影子价格以及无效决策单元的改进的非参数DEA模型,然后通过一个算例进行实证分析,将这个新的模型和经典的SBM模型进行比较,结果显示两者的相关系数超过0.9,而且这一新模型还显示出一些SBM模型所没有的优良特性.这种新的非参数方法不仅能够对环境效率水平进行测度评价,而且相较于参数方法而言,它不需要事先设定规范的函数形式,对指标数据也不需要考虑计量单位问题,具有比较独特的优势.

To construct an improved non-parametric DEA efficiency model which considers undesirable output, shadow price and ineffective decision-making units, this article establishes a non-parametric DEA efficiency model which takes undesirable output into account, demonstrates the effective necessary and sufficient condition of DEA from the perspective of shadow price, and calculates improvable amount of invalid DMUs. Then, based on an example, this article makes an empirical analysis. The correlation coefficient between the results derived from the new model and those derived from the classical SBM model is more than 0.9. At the same time, the new model is superior to the SBM model ： this new non-parametric method can measure the level of environmental efficiency; also, it does not to need to establish the normative function form beforehand, nor does it need to consider the measurement unit of index data.