Christine P. Chai’s contribution to the discussion of “A system of population estimates compiled from administrative data only” by Dunne and Zhang
本文介绍了一个仅基于行政数据的人口估计系统（PECADO），用于爱尔兰在没有中央人口登记册的情况下估算年度人口，并与2011和2016年普查结果对比，帮助研究普查漏计问题。
This paper presents a novel system of annual Population Estimates Compiled from Administrative Data Only (PECADO) for Ireland in the absence of a Central Population Register.The system is entirely based on data originated from administrative sources, so that population estimates can be produced even without purposely designed coverage surveys or a periodic census to recalibrate estimates.It requires several extensions to the traditional Dual System Estimation (DSE) methodology, including a restatement of the underlying assumptions, a trimmed DSE method for dealing with erroneous enumerations in the administrative register, and a test for heterogeneous capture probabilities to facilitate the choice of blocking in applications.The PECADO estimates for years 2011-2016 are compared to the Census counts in 2011 and 2016.We demonstrate how the system can be used to investigate the Census 2016 under-count in Ireland, in place of the traditional approach of deploying additional population coverage surveys.