The original CHAT paper had a total of 226 subjects in the surgery arm (early adenotonsillectomy), however in the version 11, there are only 224 subjects in the surgery arm using variable 'had_surgery'. Is there an explanation for the different number of subjects? Is there another surgery arm variable I should use?
I am new to CHAT and I am having a hard time distinguishing between variables from the baseline and follow up datasets. Version 7 capitalized the baseline variable names, but that is not the case for version 11. How do I tell a difference between the baseline and follow up variables?