State and local governments across the United States of America (USA) were hit hard by the recent recession. The fiscal stress alerted the public to the increasing amount of public pension debt for which, despite snowballing levels of pension debt, the causes are unclear. This article examines the factors contributing to annual changes in unfunded public pension ratios, focusing in particular on public pension management (including investment performance, investment assumptions, and accounting practices). The data on pension debt for state defined benefit plans comes from the Pew Charitable Trusts for the period 2005 to 2015. Two methods (random-effects and general estimating equation) were used to verify the consistency of the results. These results showed that investment return decreases the annual change in the public pension debt while using a project unit credit method, and the implementation of the Government Accounting Standards Board (GASB) Statement 67 increase the annual change in the public pension debt. These findings illustrate the importance of public pension management in explaining public pension debt.

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美国各州公共养老金债务的决定因素

最近的经济衰退使美利坚合众国（美国）的州和地方政府遭受了沉重打击。财政压力提醒公众注意公共养老金债务的数量不断增加，尽管养老金债务水平飞涨，但其原因尚不清楚。本文研究了导致无经费公共养老金比率每年变化的因素，特别是公共养老金管理（包括投资绩效，投资假设和会计惯例）。国家确定的福利计划的养老金债务数据来自皮尤慈善信托基金会（Pew Charitable Trusts）2005年至2015年期间的数据。使用两种方法（随机效应和一般估计方程式）验证结果的一致性。这些结果表明，投资收益减少了使用项目单位贷记法的公共养老金债务的年度变化，并且政府会计标准委员会（GASB）声明67的实施增加了公共养老金债务的年度变化。这些发现说明了公共养老金管理在解释公共养老金债务方面的重要性。