负方差元件和大小大于1的截面斜率相关性:这样的"非正规"随机截面和斜率模型是如何出现的,当它们出现时应该做些什么?
Helen Bridge1, Katy E Morgan2, Chris Frost2
1Alumna, London School of Hygiene and Tropical Medicine, London, UK.
Statistics in medicine
|May 2, 2024
概括
使用随机拦截和斜率 (RIAS) 的统计模型可以产生非正规估计. 这些非正规的RIAS模型,由于特定的数据条件或错误的规范,仍然可以允许无偏见的固定效应推断.
科学领域:
- 统计 统计 统计 统计
- 生物统计学 生物统计学
- 纵向数据分析 纵向数据分析
背景情况:
- 随机拦截和斜率 (RIAS) 模型是纵向数据的标准.
- 模型拟合可以产生非正规的估计,如负方差元件或边界相关性.
研究的目的:
- 研究导致非正规RIAS模型的条件和机制.
- 探索这些非正规模型对数据分析和解释的影响.
主要方法:
- 利用自值理论来分析RIAS模型的参数空间.
- 检查的条件包括测量频率,随访持续时间和剩余差异.
- 考虑模型错误规范,例如忽略非线性或省略随机效应.
主要成果:
- 非正规的RIAS模型更有可能有更少的测量,更短的后续和更大的残余方差.
- 模型的错误规范,包括忽略非线性或省略随机效应,可以诱导非规律性.
- 非正规模型有时可能代表有规律模型,具有无法识别的额外随机效应.
结论:
- 由于参数化限制,非正规的RIAS模型仅在特定情况下才是可信的数据生成器.
- 适应非正规的RIAS模型可以被接受为无偏的固定效应推理,避免偏差来自替代模型简化.
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