基于企业技术创新激励的环境工具的最优选择——利用排序多元Logit模型及离散计数数据模型的实证分析

Optimal choice of environmental policy instrument based on enterprises' incentive to technology innovation——empirical study by using ordered logit model and models for count data

以往关于环境政策工具对企业技术创新激励效应的研究都是基于简单的线性回归分析,不能对环境政策工具的企业技术创新激励效应进行明确的比较与排序。有鉴于此,本文首先采用排序多元Logit模型,基于上海市相关数据,对排放标准、排污费、补贴及排污许可证,四种环境政策工具进行比较与排序。研究发现,工业废水排放量、废气排放量与政府对该产业施行的环境政策工具从补贴、排放许可证、排污费到排放标准的选择概率成反比;产业集中度、技术创新与政府对该产业施行的环境政策工具从补贴、排放许可证、排污费到排放标准的选择概率成正比。其次,本文通过模型预测发现,上海市各产业目前实际实施的环境政策工具与预测环境政策工具之间存在差异,并得出各产业的最优环境政策工具的选择。最后,通过离散计数数据模型得出,四种环境政策工具对企业技术创新都有正的激励效应,其排序为:补贴、排污费、排污许可证、排放标准。研究成果可以为政府选择最优环境政策工具提供决策依据。

The previous researches about environmental policy instruments on firm technology innovation incentive effect are based on simple linear regression analysis, which can not make a clear comparison and sorting of technological innovation incentive effect aroused by different environmental policy instruments. Accordingly, based on the relative data of Shanghai, this paper uses Sort - Multiple - Logit Model to make comparison and sorting of four environmental policy instruments--Emission Quota, Emission Fee （Tax） , Subsidy and Tradable Permit. We find that the emissions of industry waste water and gas is in inverse proportion with the probability of selection of instruments, chosen by government for this industry, from Subsidy, Tradable Permit, Emission Fee to Emission Quota; industry concentration, technological innovation is proportional to the probability of selection of instruments, chosen by government for this industry, from Subsidy, Tradable Permit, Emission Fee to Emission Quota. Secondly, with the prediction of the model, we find that in Shanghai, the current environmental policy instruments chosen for different industries differ from the forecasted effects of the instruments, so this article also emerges the best choices to environmental policy instruments for kinds of industry. Finally, the paper obtains by Discrete - Count - Data Model so that we find four environmental policy instruments all have positive incentive effect on firm technology innovation, and the order is： Subsidy, Emission Fee, Tradable Permit and Emission Quota. The research results can provide government basis for decision making in the selection of the optimal environmental policy instruments.