Hi,
my problem is twofold. I downloaded a database containing gvkey, sic code, year (1995 - 2005), year-end date, and 13 variables, for about 3000 US companies. This information is organized in columns, with the first company taking the first 11 rows (years), directly followed by the next company. I have to create new variables that represent year-to-year change. I was unable to find the syntax for this command, although I assume this to be quite straightforward (like in Excel). The second problem is the necessary leap from one company to the next. How do I tell STATA to end the subtraction at the end of a certain company (year 2005), to continue with the next. Is this even possible?