标题： 多年期估计中美国社区调查趋势的不一致 显示英文标题

标题： Incompatibility of trends in multi-year estimates from the American Community Survey

摘要： 美国社区调查（ACS）为每个“社区”提供了各种人口和社会经济变量的一年（1y）、三年（3y）和五年（5y）多年估计值（MYEs），尽管对于人口较少的社区，一年和三年的数据可能不可用。 这些调查估计值并不是真正测量相同的数量，因为它们覆盖的时间跨度各不相同。 使用一些简单的模型，我们证明了比较不同时间段的MYEs会导致关于趋势变化的虚假结论。 提出了一种利用加权平均的简单方法，以减少在比较不同MYEs趋势时固有的偏差。 这些加权平均是非参数的，只需要较短的数据跨度，并且设计用于保留与趋势相关的时间序列的多项式特性。 基本方法仅需要多项式代数，已概述并应用于ACS数据。 在某些情况下，可比性有所提高，但最终结论仍需等待更多的ACS数据。 我们得出结论，不同时间段的MYE数据是不可比的。 显示英文摘要

摘要： The American Community Survey (ACS) provides one-year (1y), three-year (3y) and five-year (5y) multi-year estimates (MYEs) of various demographic and economic variables for each "community", although the 1y and 3y may not be available for communities with a small population. These survey estimates are not truly measuring the same quantities, since they each cover different time spans. Using some simplistic models, we demonstrate that comparing different period-length MYEs results in spurious conclusions about trend movements. A simple method utilizing weighted averages is presented that reduces the bias inherent in comparing trends of different MYEs. These weighted averages are nonparametric, require only a short span of data, and are designed to preserve polynomial characteristics of the time series that are relevant for trends. The basic method, which only requires polynomial algebra, is outlined and applied to ACS data. In some cases there is an improvement to comparability, although a final verdict must await additional ACS data. We draw the conclusion that MYE data is not comparable across different periods.