Design and Inference for Hybrid Ecological Studies

描述(由申请者提供)：生态研究可以被定义为在团体层面上检查协会。它们之所以吸引人，是因为它们利用了常规可用的数据，而且由于人口众多和广泛的曝光对比，它们也提供了强大的潜力。然而，它们也容易受到关于个体层面的联系的一系列偏见的影响，统称为生态偏见，并可能导致生态谬误。在流行病学中，根本的困难是生态数据无法表征暴露和混杂因素的组内差异。这导致无法控制混淆，以及个体水平模型的一般不可辨识性。生态推断问题的唯一解决方案是用个体水平的样本补充生态数据；在这项建议中，我们描述并开发了各种追求这一解决方案的混合研究。具体地说，我们开发了一种混合设计，其中病例对照研究嵌入了生态研究。直观的吸引力在于，个人层面的数据为控制偏见提供了基础，而生态数据则提供了效率收益。此外，我们将现有的方法，包括聚合数据设计法和两阶段法，扩展到生态环境中。这将基于针对这些设计的贝叶斯方法的发展，这些方法还没有被探索过。此外，我们还将比较各种方法在各种数据/采样场景中的性能。一个关键的研究问题是，群体一级的数据是否为收集个人提供了有用的信息。我们将探索最优的研究设计，从多少个个体和从哪个群体中进行抽样。这些方法用两个癌症数据集和一个流感数据集进行了说明。

DESCRIPTION (provided by applicant): Ecological studies may be defined examining associations at the group level. They are appealing in that they make use of routinely available data, and also offer the potential of high power due to large populations and broad exposure contrasts. However, they are also susceptible to a range of biases with respect to individual-level associations, collectively termed ecological bias, and may lead to the ecological fallacy. In epidemiology, the fundamental difficulty is the inability of ecological data to characterize within-group variability in exposures and confounders. This results in an inability to control for confounding, and general non-identifiability of the individual-level model. The only solution to the ecological inference problem is to supplement ecological data with individual-level samples; in this proposal we describe and develop a variety of hybrid studies that pursue this solution. Specifically, we develop a hybrid design in which a case-control study is embedded within an ecological study. The intuitive appeal is that the individual-level data provide the basis for the control of bias, while the ecological data provide efficiency gains. In addition, we extend current methods, including the aggregate data design and two-phase method, to the ecological setting. This will be based on the development of Bayesian methods for these designs, which have not been explored. Further, we will compare performance of the various methods in a variety of data/sampling scenarios. A key research question is whether the group-level data provide useful information for the collection of individuals. We will explore optimal study design in terms of how many individuals to sample and from which groups. The methods are illustrated with two cancer data sets and one influenza data set.