Social policies have great potential to improve population health and reduce health disparities. Increasingly, those doing empirical research have sought to quantify the health effects of social policies by exploiting variation in the timing of policy changes across places. Multiple social policies are often adopted simultaneously or in close succession in the same locations, creating co-occurrence that must be handled analytically for valid inferences. Although this is a substantial methodological challenge for researchers aiming to isolate social policy effects, only in a limited number of studies have researchers systematically considered analytic solutions within a causal framework or assessed whether these solutions are being adopted. We designated 7 analytic solutions to policy co-occurrence, including efforts to disentangle individual policy effects and efforts to estimate the combined effects of co-occurring policies. We used an existing systematic review of social policies and health to evaluate how often policy co-occurrence is identified as a threat to validity and how often each analytic solution is applied in practice. Of the 55 studies, only in 17 (31%) did authors report checking for any co-occurring policies, although in 36 studies (67%), at least 1 approach was used that helps address policy co-occurrence. The most common approaches were adjusting for measures of co-occurring policies; defining the outcome on subpopulations likely to be affected by the policy of interest (but not other co-occurring policies); and selecting a less-correlated measure of policy exposure. As health research increasingly focuses on policy changes, we must systematically assess policy co-occurrence and apply analytic solutions to strengthen studies on the health effects of social policies.

中文翻译：

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当一切同时发生时该怎么办：估计共同发生的社会政策对健康影响的分析方法

社会政策在改善人口健康和减少健康差异方面具有巨大潜力。越来越多的实证研究人员试图通过利用各地政策变化时间的差异来量化社会政策对健康的影响。多项社会政策通常在同一地点同时或相继采用，造成必须分析处理才能得出有效推论的同时发生。尽管这对旨在隔离社会政策影响的研究人员来说是一个巨大的方法论挑战，但只有在有限数量的研究中，研究人员系统地考虑了因果框架内的分析解决方案或评估是否采用了这些解决方案。我们指定了 7 个策略共现的分析解决方案，包括努力解开个别政策的影响和努力估计共同发生的政策的综合影响。我们使用现有的社会政策和健康系统审查来评估政策共现被识别为有效性威胁的频率以及每种分析解决方案在实践中应用的频率。在 55 项研究中，只有 17 项 (31%) 的作者报告检查了任何共现政策，尽管在 36 项研究 (67%) 中，至少使用了一种方法来帮助解决政策共现问题。最常见的方法是针对同时发生的政策措施进行调整；定义可能受利益政策影响的亚群的结果（但不是其他同时发生的政策）；选择一个相关性较低的政策风险衡量指标。