论文标题
观察纵向研究的设计
The Design of Observational Longitudinal Studies
论文作者
论文摘要
本文考虑了观察性纵向研究的设计，并具有连续的响应和二进制时间不变的暴露，通常情况下，暴露是不平衡的，在基线时两组的平均响应在基线时有所不同，并且测量时间可能并不相同。我们认为群体差异是恒定的，以及随着时间的线性增加的群体差异。我们研究功率，研究参与者的数量（N）和重复测量的数量（R），并在其他两个固定时为每个数量提供公式，用于化合物对称性，抑制指数和随机截距和斜率协方差。当研究人员可以选择N和R时，我们研究了最大化功率的最佳组合，但要受到成本限制，并最大程度地减少了固定功率的成本。直观参数化用于所有数量。所有计算均在免费的软件中实现。
This paper considers the design of observational longitudinal studies with a continuous response and a binary time-invariant exposure, where, typically, the exposure is unbalanced, the mean response in the two groups differs at baseline and the measurement times might not be the same for all participants. We consider group differences that are constant and those that increase linearly with time. We study power, number of study participants (N) and number of repeated measures (r), and provide formulas for each quantity when the other two are fixed, for compound symmetry, damped exponential and random intercepts and slopes covariances. When both N and r can be chosen by the investigator, we study the optimal combination for maximizing power subject to a cost constraint and minimizing cost for fixed power. Intuitive parameterizations are used for all quantities. All calculations are implemented in freely available software.
