The defined convex combination (DCC) pay-as-you-go public pension systems recently introduced in the literature are a form of hybridization between defined benefit (DB) and defined contribution (DC) designed to maintain intergenerational social equitability by reacting to demographic shocks in an optimal way. In this paper, we augment DCC schemes with the assumption that the dependency ratio between pensioners and workers is driven by an exogenously modelled instantaneous stochastic rate of change. This assumption enjoys support from the empirical data and allows explicit solutions for the contribution and replacement rate processes which make transparent the nature of the dynamic evolution of a DCC system, as well as the role of the variables involved. The analysis of intergenerational social equitability measures under the assumption of an instantaneous dependency rate confirms the view expressed in previous literature that neither DB nor DC achieves social fairness, and that DCC plans have the potential to improve on both. We perform a calibration test, and our findings seem to indicate that in ageing economies the DC system might indeed be superior to the DB one in terms of intergenerational fairness.

最近在文献中引入的定义凸组合（DCC）随用随付公共养老金系统是定义福利（DB）与定义缴款（DC）之间的一种混合形式，旨在通过对人口变化的冲击做出反应来维持代际社会公平性以最佳方式。在本文中，我们假设养老金领取者和工人之间的抚养比是由外生模型化的瞬时随机变化率驱动的，从而增强了DCC方案。该假设得到了经验数据的支持，并为贡献和替换率过程提供了明确的解决方案，这些过程使DCC系统动态演化的本质以及所涉及变量的作用变得透明。在瞬时受抚养人比率的假设下对代际社会公平性措施进行的分析证实了先前文献中表达的观点，即DB和DC都无法实现社会公平，DCC计划在这两者上都有改进的潜力。我们进行了一项校准测试，我们的发现似乎表明，在老龄化经济体中，就代际公平性而言，DC系统的确可能优于DB系统。