topic Re: how to refer to a previous value in longitudinal data set in Statistical Procedures

how to refer to a previous value in longitudinal data set

deerdi — Mon, 05 May 2014 21:23:27 GMT

I am working with a longitudinal data; students received a degree at a certain time; I wonder how I can change all the values to 1 after degree attainment. For example, this is what my data looks like now:

Id time award

1 1 .

1 2 .

1 3 1

1 4 .

1 5 .

What I would like to do is to change the two missing values for time=5 and time=6 into 1. Any help is appreciated~!

Re: how to refer to a previous value in longitudinal data set

PGStats — Mon, 05 May 2014 22:06:05 GMT

This way, assuming your data is sorted by id and time:

data have;

input Id time award;

datalines;

1 1 .

1 2 .

1 3 1

1 4 .

1 5 .

;

data want;

do until(last.id);

set have; by id;

gotIt = coalesce(gotIt, award);

award = gotIt;

output;

end;

drop gotIt;

run;

proc print data=want noobs; run;