Skip to main content
. 2009 Dec 11;103(2):99–108. doi: 10.1093/qjmed/hcp169
Xij: the covariates (in this case the confounders) describing the patients characteristics of patient j in hospital i, including the constant term,
β: the regression coefficients describing the effect of the covariates and the intercept,
θi: the effect of hospital i, that is the coefficient with respect to some overall mean, drawn from a normal distribution with mean µ and variance