I am running a logistic regression analysis to model if a patient has a specific disease or not.
I want to remove outliers because i want my model to be as accurate as possible. For the same I learnt that in SAS proc logistic one can obtain Standardized Deviance Residuals and Likelihood Residuals. The observations with values of aforementioned residuals greater than 2 or less than -2 needs to be investigated as outliers.
My question is do I run Proc logistic on full data set or just the training data set(70% of full data set) for outliers removal? Do I have to remove outliers on full data set (meaning both training & test data sets will have outliers removed) or just remove outliers from training data set and let test data set have outliers?