根据数据类型，logistic回归分为两种：一种是条件logistic回归，用于分析配对病例对照研究，另一种是非条件logistic回归，用于分析成组数据或非配对的病例对照研究。非条件ligostic回归简称logistic回归分析。

文件里第一节有讲非条件logistic产生的偏差。希望对你有帮助：）

“Conditional” regression – what do we mean?
(a) Have levels of strata (age category) or centers (hospitals) or pairs (matched)
(b) Wish to estimate association of a within-strata exposure (drug exposure) and outcome
(c) Have different intercept for each stratum, but these levels are “nuisance” parameters –
we do not care about them, and we cannot estimate them using this method. They are
“conditioned out” of the analysis
(d) We want to condition these out in order to address the problem of heterogeneity in the
baseline risk (the risk of outcome in the reference group of patients)