st: backfill missing data

[David Torres <torresd@umich.edu>]

I'm working with longitudinal data (12 rounds of info collected so  
far) and need to backfill information for respondents who were not  
interviewed in a given year subsequent to round 1.  Information on my  
variables of interest, when not collected in a round due to  
noninterview, can be gathered in the next round in which respondents  
are interviewed.  I'd like to carry that information back so that it  
fills in the missing cells in the year and job number to which it  
should apply.
I've concatenated unformatted date variables for each year and job  
number so that start and finish dates for a job are carried back  
together.  Every pair of numbers, then, including the space in  
between, represent a start and finish date.  All dates here, though  
for example purposes only, are year specific.  An example of what I  
have, then, is:
pubid stfin1_1998 stfin2_1998 stfin1_1999 stfin2_1999 stfin1_2000 stfin2_2000
1     13901 14200 14100 14200                         14247 14590
2     13890 14198                                     14310 14525
3                                                     14000 14208 14311 14915
4                             13883 14650 14351 14600 14635 14900

For pubid 1, the values in stfin1_2000 would be copied to stfin1_1999  
as it applies to that year.  The same goes for pubid 2.  In pubid 3,  
stfin1_2000 should be copied to stfin1_1998 as it applies to that  
year; stfin2_2000 should be copied to stfin1_1999 since it applies to  
that year.  In pubid 4, stfin1_1999 should be copied to stfin1_1998.   
I only mean to copy follow-up year information to cells for which  
current year information is missing, or ". ."
Is there an easy way to do this across several years and job numbers  
at the same time?  Perhaps using a foreach command?
Cheers,
--------------------------------------------

David Diego Torres, MA(Sociology)
PhD Candidate in Sociology

2044 Population Studies Center
University of Michigan Institute for Social Research
Ann Arbor MI  48106-1248
Tel 734.763.4098
Fax 734.763.1428
torresd at umich dot edu
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