Impact of Asking Race Information in Mail Surveys
作者通过实地实验，在四个地区测量了邮件调查中询问种族信息的影响。控制组和测试组的问卷均为六页，唯一区别是测试组增加了种族相关问题。结果发现，两组的回复率完全相同。
A field experiment was carried out in four regions to measure the impact of asking race information in a mail survey. The six-page questionnaire was identical between control and test groups except for the addition of questions on race information. The response rates for both groups were identical.