Estimating the number of individuals living in a country is an essential task for demographers. This study assesses the potential bias in estimating the size of different migrant populations due to over-coverage in population registers. Over-coverage—individuals registered but not living in a country—is an increasingly pressing phenomenon; however, there is no common understanding of how to deal with over-coverage in demographic research. This study examines different approaches to and improvements in over-coverage estimation using Swedish total population register data. We assess over-coverage levels across migrant groups, test how estimates of age-specific death and fertility rates are affected when adjusting for over-coverage, and examine whether over-coverage can explain part of the healthy migrant paradox. Our results confirm the existence of over-coverage and we find substantial changes in mortality and fertility rates, when adjusted, for people of migrating age. Accounting for over-coverage is particularly important for correctly estimating migrant fertility.

中文翻译：

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人口登记的过度覆盖导致人口估计的偏差。

估计生活在一个国家的人口数量是人口统计学家的一项基本任务。本研究评估了由于人口登记过度覆盖而在估计不同移民人口规模时的潜在偏差。过度覆盖——个人注册但不在一个国家生活——是一个日益紧迫的现象；然而，对于如何处理人口研究中的过度覆盖并没有达成共识。本研究使用瑞典总人口登记数据研究了不同的方法和改进过度覆盖估计。我们评估移民群体的过度覆盖水平，测试在调整过度覆盖时对特定年龄死亡率和生育率的估计如何影响，并检查过度覆盖是否可以解释健康移民悖论的一部分。我们的结果证实了过度覆盖的存在，我们发现在调整后，移徙年龄人群的死亡率和生育率发生了重大变化。考虑过度覆盖对于正确估计移民生育率尤为重要。