When you consider Year 2000 as it applies to SAS, you have to consider both SAS itself and your own methodologies. The program SAS is expected to be Y2K compliant, in that it will continue to run after January 1, 2000. (You can check SAS Institute's Year 2000 web site for the latest product news and information.) For most users, the main issue will be data and procedure compliance.

First of all, you should investigate how years are stored in your data. Ideally, they should all use four digits. If they do not, there must be a unique rule for determining which century they fall in. This may require talking to any agencies that supply you with data to determine what standards they use.

Second, you should see how your program handles year data. Do you use SAS's date formats? If you do not, you must make any and all corrections to date computations yourself. Be especially watchful for two-digit years stored as numeric variables, which are then used for determining lengths of time or comparisons.

If you do use SAS's date formats, you should make sure that you know how SAS is interpreting your data. SAS uses an option called YEARCUTOFF= to determine what 100-year window two-digit years fall into. The default value of YEARCUTOFF= is 1900, which means that all two-digit years are assumed to take place in the 1900s. The default will change to 1920 in System 7. In anticipation of this change, the default value of YEARCUTOFF= on bama was changed to 1920 on 04/16/1999.

You can check the value of YEARCUTOFF= by running the following program:
proc options option=yearcutoff;
run;

To change the value of YEARCUTOFF= used by all of your work, you should create an autoexec.sas file. If you are using SAS on PC, the autoexec.sas file should go in your SAS directory. If you are using SAS on bama, the autoexec.sas file should go in your home directory. The autoexec.sas file should contain the following line:
options yearcutoff=19xx

To change the value of YEARCUTOFF= used by a particular program, you can simply include the above line at the beginning of that program.

An example of the use of YEARCUTOFF= and date formats is available.

SAS has also released instructions on reading in date values that use a century indicator instead of the four-digit year. Please see http://www.sas.com/service/techsup/unotes/V6/F677.html for numeric dates and http://www.sas.com/service/techsup/unotes/V6/F682.html for character dates.

A very good explanation of the testing procedure is given in Testing Your SAS Software Applications for Year 2000 Compliance, on the SAS Institute Year 2000 site.

There is also a SAS Year 2000 discussion forum sponsored by Qualex Consulting Services. It can be found at http://www.qlx.com/forumy2k/.

You are responsible for the integrity of your own projects and data. If you are beginning a project now, you should make sure that you use four-digit years whenever possible. However, if you have an older project with legacy data, you need to start immediately making sure that data from the new century does not lead to erroroneous results.