If you need to add (or subtract) a period measured in days to a date, it is straightforward to do so. Just remember to format all new date variables as dates with %td:

Code:
gen a = td(19oct2005) - 28
format %td a
My question is that, in all cases, I don't need a variable. I only need to know the outcome. Even if I generate a new variable, it's useless for me and I will drop it. Thus, I am thinking that just generate a scalar. But then I realize that format %td a will not work for a scalar.