st: Duration data- count number of spells with ref to current spell

[Sriram Narayanamoorthy <nsriram@utexas.edu>]

Hello everyone,

This question is on data generation when working with a
discrete-duration datasets. The dataset I have includes all the
activities undertaken by individuals in a 24 hour period. The day is
divided into 48 half-hour intervals. The start interval of a spell is
denoted by a variable called eventStart. The activity type is denoted
by the variable eventType.

The task of counting the number of activities of a particular type
undertaken in a day by the person is quite straightforward using egen.

However, I want to generate a variable as the number of activities of
a particular type undertaken by the individual before/after the
current activity. How do I add the "Before" and "After" dimension to
my variable? To be sure, I want to compare the eventStart of my
current record with all other records for that person and count the
number of records of a particular eventType only if eventStart is less
than (for Before) or greater than (for After) the current start
period.

Any thoughts? Is there a mata approach to this? Thanks much for the inputs!

Thanks,
-Sriram
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