How can I get 0's for a variable before an observation and 1's after?

[yanagi]

My data is a panel of industry-years. Some industry-years have a value of 1 for an indicator variable "PERSISTENT." (Otherwise, PERSISTENT is missing.) Some industries do not have any years for which PERSISTENT is 1, and the years in which PERSISTENT takes on a value of 1 may vary by industry.

How can I recode PERSISTENT such that it takes on values of 0 before the industry-year observation that currently has a 1 AND takes on values of 1 for all industry-years afterward?

[Reeza]

Show what your data looks like, is it long or wide?

[yanagi]

Industry	Year	PERSISTENT
11	1992
11	1993
11	1994
11	1995	1
11	1996
11	1997
11	1998
11	1999
11	2000
11	2001
11	2002
11	2003
11	2004
11	2005
11	2006

That's an example of what the data looks like. I guess that's long?

[Reeza · Accepted solution]

data want;

by industry;

retain flag;

if first.industry then flag=0;

if persistent=1 then flag=1;

run;

[yanagi]

Thank you so much. I was vastly overthinking it (thought I needed to do an array).