I am having problem deciding wheter to define a variable as a random effect to include in our logistic regression model. Any help on this subject would be most appreciated.
In this model, we are trying to determine the effect of region of residence on different endpoints after hospital admissions. We have included several demographic and hospital variables as fixed effects as well as region.
Due to the fact that most people from regions are hospitalized in their regional hospital, each hospital is highly correlated with region.
Is it appropriate to use hospital (as a categorical variable) as a random effect to control for the potential bias in the varying quality of care between hospitals?