Between July 2005 and July 2007, the Oregon Supplemental Nutrition Program for Women, Infants and Children program conducted the largest randomized field experiment (RFE) ever in the United States to assess the effectiveness of a low-cost peer counseling intervention to promote exclusive breastfeeding. We undertook a within-study comparison of the intervention using unique administrative data between July 2005 and July 2010. We found no difference between experimental and nonexperimental estimates but failed to determine correspondence based on more stringent criteria. We show that tests for nonconsent bias in the benchmark RFE might provide an important signal as to confounding in the nonexperimental estimates.

中文翻译：

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非实验方法能否提供母乳喂养干预的无偏估计？俄勒冈州同伴咨询的研究范围内的比较。

在2005年7月至2007年7月之间，俄勒冈州妇女，婴儿和儿童补充营养计划进行了美国有史以来最大的随机田野试验（RFE），以评估低成本同伴咨询干预措施促进纯母乳喂养的有效性。我们在2005年7月至2010年7月期间使用独特的行政数据对干预措施进行了研究内比较。我们发现实验估计值与非实验估计值之间没有差异，但未能根据更严格的标准确定对应关系。我们表明，基准RFE中不一致同意偏差的测试可能会提供一个重要信号，说明在非实验性估计中会产生混淆。