Date:         Tue, 18 Mar 2008 15:47:07 -0400
Reply-To:     Dave Diggs <diggs.dave@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Dave Diggs <diggs.dave@YAHOO.COM>
Subject:      Tricky - Differences

I have the following data:

USERID              Date                            SurveryScore
123                01/01/06                             120
123                01/03/06                             200
123                01/05/06                             150
123                01/07/06                             220
234                01/05/06                             180
234                01/06/06                             190
345                01/02/06                             250
456                01/01/06                             110
456                01/04/06                             170

I want to create another column of differences of rows from the
surveryScore column such that I can create another dataset as follows:

USERID    Date       SurveryScore    Diff
123     01/01/06       120            0
123     01/03/06       200            80
123     01/05/06       150           -50
123     01/07/06       220            70
234     01/05/06       180             0
234     01/06/06       190            10
345     01/02/06       250            0
456     01/01/06       110            0
456     01/04/06       170            60

How can I do this is SAS. Thank you.
Dave