I'm struggling to convert a duration-type data set (survival data) into a
"discretised" montlhy panel data. For example, suppose that one individual
(id) displays for his first observation: (entry=1Sep1994; exit=31Oct1994;
failure=1), and for his second observation: (entry=1Nov1994; exit=30Nov1994;
failure=0). I want to arrange these in a typical (long) panel data shape,
where I'd have: