How do I lag the exposure to outcome by a year?

[Revere2323]

Hello,

I am looking to lag the exposure to outcome by a year. What I mean by this is that for a given year in my data, I want the exposure in one year to be associated with the outcome in the next, instead of the same year. This is because I want to avoid reverse causation. 

So if the exposure for 1999 is 26, I would want it to match with the outcome for 2000.

Here is my code without the lag:

PROC GENMOD data=data1;
CLASS StateID year (ref=first) event (ref=first);
MODEL Outcome =Exposure confounder / DIST=poisson LINK=log TYPE3 WALD offset=lnpop; 
REPEATED SUBJECT=stateid;
run;

I have an offset of state population and a repeated subject on stateID. Outcome is my main outcome and exposure is my main exposure. Confounder is a confounder. I do not think that the confounder should be lagged, just the main exposure and outcome.

Thanks so much!

[PGStats]

You could run your analysis on table data2 given by:

proc sql;
create table data2 as
select 
    a.*,
    b.Exposure as lastYearExposure
from 
    data1 as a inner join 
    data1 as b on a.stateId = b.stateId and b.year = a.year-1;
quit;

(untested)