Objectives

This study derives the statistical power of the common hit rates test of taste-based discrimination in police searches. It also identifies search intensity as a source of bias in the test and proposes a simple empirical adjustment to account for the bias.

Methods

Data simulations, along with two empirical applications to motor vehicle search data, display the practical importance of both statistical power and search intensity bias in the hit rates test.

Results

Statistical power varies markedly with the parameters of the application. Differential search intensity across groups will bias results, but the simple empirical adjustment provides a valid test when the data contain a discrete indicator of search intensity. In the empirical applications, unadjusted and adjusted tests differ in their conclusion of whether police discrimination exists.

Conclusions

For the presentation of multiple hit rates tests, statistical power should be reported with p-values. Theoretical bounds on search intensity bias are wide, and the bias can persist for any sample size. Hit rates tests should therefore be interpreted with caution when data contain no indicator of search intensity.

中文翻译：

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判别命中率测试中的统计功效和搜索强度偏差

目标

本研究得出了警察搜查中基于品味的歧视的常见命中率测试的统计功效。它还将搜索强度确定为测试中的偏差来源，并提出了一个简单的经验调整来解释偏差。

方法

数据模拟以及对机动车辆搜索数据的两个经验应用，显示了统计能力和搜索强度偏差在命中率测试中的实际重要性。

结果

统计功效随应用程序的参数而显着变化。不同组之间的差异搜索强度会使结果产生偏差，但当数据包含搜索强度的离散指标时，简单的经验调整提供了有效的测试。在实证应用中，未经调整和调整的测试对警察歧视是否存在的结论不同。

结论

对于多个命中率测试的呈现，应使用p值报告统计功效。搜索强度偏差的理论界限很宽，并且偏差可以持续任何样本大小。因此，当数据不包含搜索强度指标时，应谨慎解释命中率测试。