The 2020 Census Disclosure Avoidance System (DAS) is a formally private mechanism that first adds independent noise to cross tabulations for a set of pre-specified hierarchical geographic units, which is known as the geographic spine. After post-processing these noisy measurements, DAS outputs a formally private database with fields indicating location in the standard census geographic spine, which is defined by the United States as a whole, states, counties, census tracts, block groups, and census blocks. This paper describes how the geographic spine used internally within DAS to define the initial noisy measurements impacts accuracy of the output database. Specifically, tabulations for geographic areas tend to be most accurate for geographic areas that both 1) can be derived by aggregating together geographic units above the block geographic level of the internal spine, and 2) are closer to the geographic units of the internal spine. After describing the accuracy tradeoffs relevant to the choice of internal DAS geographic spine, we provide the settings used to define the 2020 Census production DAS runs.

翻译：2020年人口普查避免披露系统（DAS）是一种正式的私密机制，首先向一组预先指定的层次地理单元-被称为地理脊柱-添加独立噪声以保护数据隐私。在对这些嘈杂的测量进行后处理后，DAS输出一个具有标准人口普查地理脊柱中的位置信息的正式私密数据库，该脊柱由整个美国、各州、县、人口普查区、街区组成。本文描述了内部在DAS中用于定义初始嘈杂测量的地理脊柱如何影响输出数据库的准确性。具体而言，地理区域的分组通常对于在内部脊柱块地理级别之上聚合地理单元且与内部脊柱地理单元更接近的地理区域最为准确。在描述了选择内部DAS地理脊柱的准确度权衡之后，我们提供了用于定义2020年人口普查生产DAS运行的设置。