Re: st: Counting Ulcers

["Dimitriy V. Masterov" <dvmaster@gmail.com>]

Try

bys id: egen type=sum(vi) if vi~=.
collapse type, by(id)

This will count people with missing observations as "." and not zero,
and it will avoid double-counting.

DVM
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/