Parker R A, Bregman D J
Biometrics. 1986 Dec;42(4):919-26.
The standard formulas used to calculate sample size for an individually matched case-control study assume a constant probability of exposure throughout the pool of possible controls. We propose new formulas that allow for heterogeneity in the probability of exposure among controls in different matched sets. Since matching factors are suspected of being confounders, they are expected to divide the total population into subgroups with different proportions exposed. Thus, the assumption of homogeneity of exposure among controls, made by the currently used formulas, is inconsistent with the assumptions used to design a matched study. The proposed formulas avoid this inconsistency. We present an example to illustrate how heterogeneity can affect the required sample size.
用于计算个体匹配病例对照研究样本量的标准公式假定在所有可能的对照群体中暴露概率恒定。我们提出了新的公式，该公式考虑了不同匹配组中对照的暴露概率的异质性。由于匹配因素被怀疑是混杂因素，因此预期它们会将总体人群划分为具有不同暴露比例的亚组。因此，当前使用的公式所做的对照中暴露同质性的假设与用于设计匹配研究的假设不一致。所提出的公式避免了这种不一致性。我们给出一个例子来说明异质性如何影响所需的样本量。
