Hi,
I am running into a problem about model selection. I am working on a validation of a questionnaire score: propr. I want to compare the propr with two other scores (sf6d and meanhs). My design is to fit the propr score as a function of binary exposure variables when accounting for age and sex as confounding variables. And do the same thing to the other scores.
Since the distribution of one score is skewed, I need to conduct a nonparametric regression. My questions are
  1. Is quantile regression or npregress model a better for current scenario? The observation is around 300, and npregress was working on STATA.
  2. If I choose quantile regression, is it possible to use median as the quantile for all the models?
Hope I stated my question clearly. Thanks!