st: Two new items on SSC: gen_tail & carryforward

[David Kantor <dkantor@jhu.edu>]

Hi everyone;

I would like to announce two packages that have been recently been added to 
the SSC archives. Both may be useful in dataset construction.

gen_tail: This generates an indicator variable, indicating the "tail end" 
of a series of observations.  The tail starts at the first nonzero value of 
the input variable and continues until the end of the dataset or by-group. 
In other words, it identifies those observations that are at or beyond a 
certain point. (I know this is simple, but I had been doing it repeatedly, 
so I made it into a program.) I have used this for censoring observations 
in time-series data.

carryforward: This will carry values forward from one observation to the 
next, filling in missing values with the previous value. It also has a 
provision to "carry along" ancillary variables. (Again, simple, but I had 
been doing it repeatedly, so I made it into a program. )

Thanks to Kit Baum for placing these in the SSC archives.
-- David

David Kantor
Institute for Policy Studies
Johns Hopkins University
dkantor@jhu.edu
410-516-5404

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