Case-control designs are an important tool in contrasting the effects of well-defined treatments. In this paper, we reconsider classical concepts, assumptions and principles and explore when the results of case-control studies can be endowed a causal interpretation. Our focus is on identification of target causal quantities, or estimands. We cover various estimands relating to intention-to-treat or per-protocol effects for popular sampling schemes (case-base, survivor, and risk-set sampling), each with and without matching. Our approach may inform future research on different estimands, other variations of the case-control design or settings with additional complexities.

翻译：案例控制设计是对比定义明确的处理方法影响的重要工具。在本文件中,我们重新考虑传统概念、假设和原则,并探索何时可以对案例控制研究的结果作出因果关系解释。我们的重点是确定目标因果数量,或估计数量。我们涵盖与普通抽样计划(案例基准、幸存者和风险定位抽样)的意向性或每程序效果有关的各种估计值,每个都与或不匹配。我们的方法可以为今后关于不同估计值、案件控制设计的其他变异或具有额外复杂性的设置的研究提供信息。