st: elapsed time between incidents

[Steven Archambault <archstevej@gmail.com>]

Hi all,

I have unbalanced panel data where an incident (measured by a non-zero
value) occurs randomly in the panel. I want to calculate the time
(days_elapsed) between incidents. Here is an example:

id day incident days_elapsed
1  1      6             .
1   2     .              .
1   3     .              .
1  4      .              .
1   5     8             4
1   6     .              .
1   7     5             2

Thanks for any help here.  I have not been able to find this.

-Steve
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/