ABSTRACT We present an increasingly stringent set of replications, a multilevel regression and poststratification analysis of polls from the 2008 U.S. presidential election campaign, focusing on a set of plots showing the estimated Republican vote share for whites and for all voters, as a function of income level in each of the states. We start with a nearly exact duplication that uses the posted code and changes only the model-fitting algorithm; we then replicate using already-analyzed data from 2004; and finally we set up preregistered replications using two surveys from 2008 that we had not previously looked at. We have already learned from our preliminary, nonpreregistered replication, which has revealed a potential problem with the earlier published analysis; it appears that our model may not sufficiently account for nonsampling error, and that some of the patterns presented in that earlier article may simply reflect noise. In addition to the substantive interest in validating earlier findings about demographics, geography, and voting, the present project serves as a demonstration of preregistration in a setting where the subject matter is historical (and thus the replication data exist before the preregistration plan is written) and where the analysis is exploratory (and thus a replication cannot be simply deemed successful or unsuccessful based on the statistical significance of some particular comparison). Our replication analysis produced graphs that showed the same general pattern of income and voting as we had found in our earlier published work, but with some differences in particular states that we cannot easily explain and which seem too large to be explained by sampling variation. This process thus demonstrates how replication can raise concerns about an earlier published result.

中文翻译：

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2008年大选：预注册的复制分析

摘要我们介绍了一系列越来越严格的复制，对来自2008年美国总统大选的民意测验进行的多层次回归和后分层分析，重点关注的一组情节显示了白人和所有选民的估计共和党投票份额与收入的关系。每个州的水平。我们从使用发布代码的几乎完全重复开始，仅更改模型拟合算法。然后，我们使用2004年以来已分析的数据进行复制；最后，我们使用之前从未查看过的2008年的两次调查来设置预注册的复制。我们已经从我们的初步非预注册复制中学到了知识，这表明较早发表的分析存在潜在的问题。看来我们的模型可能不足以解决非抽样误差，并且该较早的文章中介绍的某些模式可能只是反映了噪声。除了对验证有关人口统计，地理和投票的早期发现具有实质性兴趣外，本项目还可以在主题为历史性的环境中（因此复制数据在编写预注册计划之前就已存在）证明了预注册。分析是探索性的（因此，根据某些特定比较的统计意义，不能简单地将复制视为成功或不成功）。我们的复制分析产生的图表显示出与我们之前发表的作品相同的一般收入和投票方式，但是在某些特定状态下存在一些差异，我们无法轻易解释这些差异，而且看起来太大了，无法通过抽样变化来解释。因此，此过程演示了复制如何引起对较早发布结果的担忧。