论文标题
通过多种治疗和不同类型的选择来确定政策改革的因果渠道
Identifying causal channels of policy reforms with multiple treatments and different types of selection
论文作者
论文摘要
我们研究了通过多种治疗方法的政策改革渠道的识别和每种治疗方法的不同类型的选择。在有条件的独立性，共同趋势以及对未处理的额外限制的假设下，我们将改革的效果分解为政策效果，选择效应和时间效应。此外，我们在对中介变量施加了其他顺序有条件的独立性假设后，显示了直接和间接策略效应的识别。我们使用德国对失业者的职业培训分配制度的改革说明了这种方法。改革将培训从强制性系统转变为自愿凭证系统的分配。同时，参与者的选择标准改变了，改革改变了课程类型的组成。我们将课程组成视为政策改革的调解人。我们表明，在考虑课程组成时，先前研究的经验证据会逆转。这对政策结论具有重要意义。
We study the identification of channels of policy reforms with multiple treatments and different types of selection for each treatment. We disentangle reform effects into policy effects, selection effects, and time effects under the assumption of conditional independence, common trends, and an additional exclusion restriction on the non-treated. Furthermore, we show the identification of direct- and indirect policy effects after imposing additional sequential conditional independence assumptions on mediating variables. We illustrate the approach using the German reform of the allocation system of vocational training for unemployed persons. The reform changed the allocation of training from a mandatory system to a voluntary voucher system. Simultaneously, the selection criteria for participants changed, and the reform altered the composition of course types. We consider the course composition as a mediator of the policy reform. We show that the empirical evidence from previous studies reverses when considering the course composition. This has important implications for policy conclusions.
