The Impact of Social Security Contributions on Earnings: Evidence using administrative data in France, Germany, the Netherlands and the UK

面对巨额预算赤字和日益增加的福利支出成本，许多国家已经或正在考虑增加社会保障缴费(SSC)。与此同时，雇主的SSC被指责有害于就业，导致各国减少SSC并增加其他税收。考虑到这些重要问题，该项目旨在利用法国、德国、荷兰和英国的大型管理小组数据，就SSC对收益的影响提供新的证据。这些大型行政数据库从未用于跨国分析，并提供了一个机会，使我们有机会在微观和宏观两个层面上大大提高我们对工资单SSC影响的了解。特别是，我们讨论了两个相关的问题：SSC对行为的影响(劳动力供求反应)和SSC的经济发生率(即谁以较低的净收入形式承担SSC的负担)。我们计划有系统地利用SSC税率的变化以及SSC结构和费率的变化来确定对收入的短期影响，并根据名义上应由谁负责纳税(即雇员或雇主)来区分影响，以及SSC的金额是否与所获得的福利金额挂钩。我们还将更新有关SSCs的长期发病率和行为影响的证据。我们的经验方法不仅包括评估所研究的特定改革的影响。我们还将采取更具结构性的方法，试图解释和了解所涉及的机制，以便我们能够预测和模拟其他改革的影响，并关注不同的劳动力市场制度(例如工资谈判)在影响SSC的行为影响和发生率方面可能扮演的角色。

Faced with large budget deficits and increasing costs of welfare spending, many countries have increased, or are considering increasing, Social Security Contributions (SSCs). At the same time, employers' SSCs have been blamed for being detrimental to employment, leading countries to reduce these and increase other taxes. With such important issues in mind, this project aims at providing new evidence on the effects of SSCs on earnings, using large administrative panel data in France, Germany, the Netherlands and the UK. These large administrative databases have never been used in a cross-country analysis and provide a chance to significantly improve our knowledge of the impact of payroll SSCs both at the micro and macro level. In particular we address two related questions: the effects of SSCs on behaviour (labour supply/demand responses) and the economic incidence of SSCs (i.e. who bears the burden of them in the form of lower net income). We plan to systematically use variation in SSC rates and changes in the structure and rates of SSCs to identify short-term impacts on earnings, distinguishing effects according to who is nominally liable for the tax (i.e. the employee or the employer) and whether the amount of SSCs is linked to the amount of benefits received. We will also update evidence on the long-run incidence and behavioural effects of SSCs. Our empirical approach consists not only of assessing the impact of the particular reforms studied. We will also take a more structural approach that seeks to explain and understand the mechanisms involved so that we can anticipate and simulate the effects of other reforms, paying attention to the role that different labour market institutions (such as wage bargaining) may play in affecting the behavioural impact and incidence of SSCs.