I am trying to introduce AR1 term into my models (lag of dependent variable). It is easy to do for the for the historic period which is lag(y). But I am wondering how to create it for the forecast period (it would actually be the lag of the prediction). Is ther any SAS procedure or autoreg can do this?? My data looks like:
Date Y lag(y) X1 X2
… .006 …. 12 7
Q1 2016 .005 .006 1 3
Q2 2016 .004 .005 11 7
Q3 2016 .003 .004 8 7
Q4 2016 .004 .003 10 6
Q1 2017 . .004 12 5
Q2 2017 . . 11 4
Q3 2017 . . 10 3
Q4 2017 . . 11 4
….
How do I populate lag(Y) for qtr’s Q2 2017 & beyond so that I can use it in regression??
Thanks in advance.