Date:         Thu, 25 Aug 2011 16:29:53 -0400
Reply-To:     sas8832@HOTMAIL.CO.UK
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         sas8832@HOTMAIL.CO.UK
Subject:      Re: Lag values

panel dataset

id year quarter variablex lag_variablex
1   2000 1         10            .
1   2000 2          5            10
1   2000 3          .             5
1   2000 4          20             .

When variablex is missing for the previous quarter, i want lag_variablex=.
rather than equal to the previous available value for variable x. I have
already filled holes (ie missing quarters).

Thanks