Department of Health Management and Policy, Department of Economics, University of Michigan, Ann Arbor, MI.
National Bureau of Economic Research, Cambridge, MA.
Health Serv Res. 2018 Apr;53(2):859-878. doi: 10.1111/1475-6773.12712. Epub 2017 May 30.
We discuss how to interpret coefficients from logit models, focusing on the importance of the standard deviation (σ) of the error term to that interpretation.
We show how odds ratios are computed, how they depend on the standard deviation (σ) of the error term, and their sensitivity to different model specifications. We also discuss alternatives to odds ratios.
There is no single odds ratio; instead, any estimated odds ratio is conditional on the data and the model specification. Odds ratios should not be compared across different studies using different samples from different populations. Nor should they be compared across models with different sets of explanatory variables.
To communicate information regarding the effect of explanatory variables on binary {0,1} dependent variables, average marginal effects are generally preferable to odds ratios, unless the data are from a case-control study.
我们讨论如何解释逻辑回归模型中的系数,重点关注误差项的标准差(σ)对解释的重要性。
我们展示了如何计算优势比,它们如何依赖于误差项的标准差(σ),以及它们对不同模型规格的敏感性。我们还讨论了优势比的替代方法。
不存在单一的优势比;相反,任何估计的优势比都是有条件的,取决于数据和模型规格。不应该在不同的研究中使用来自不同人群的不同样本来比较优势比。也不应该在具有不同解释变量集的模型之间进行比较。
要传达有关解释变量对二元{0,1}因变量的影响的信息,平均边际效应通常优于优势比,除非数据来自病例对照研究。