Assessing and comparing the effects of public policies – a new approach
提出一种名为“公共政策条件效果”的贝叶斯方法，用于在特定政策组合中评估单项政策对某一结果的影响，并以波特假说为例分析环境政策对绿色创新的作用。
Assessing the effects of public policies is essential for academic and practical reasons. While existing approaches focus on the effects of individual policies or entire sectoral policy regimes, approaches that evaluate individual policies within the context of sectoral policy mixes are missing. This paper introduces a middle-ground approach called the Conditional Effects of Public Policies (CEPP) method. The CEPP approach uses a Bayesian-based procedure to (1) capture all policies in a specific area aimed at a particular outcome and (2) compare each policy’s effect on that outcome. We demonstrate the analytical value of our approach for the ‘Porter Hypothesis’ in order to distinguish between environmental regulations that hinder or promote green innovations. Covering 21 OECD countries over two decades we show that while no environmental policy is universally ‘good’ or ‘bad’ in this regard, public investment programmes tend to be a driver of innovation. Hierarchical instruments by contrast show varied effects. Taken together, this paper not only provides a new method to assess policy effects in times of increasingly congested policy spaces, but also makes a clear contribution to a contested question in policy research, namely, whether and under which conditions environmental policies can offer benefits for the regulated companies.