If the dates in your external data files have 4-digit years, you should have no problem, SPSS System will read and write those 4-digit years correctly. If the dates in your external data files have 2-digit years, please read the following statements to ensure that the 2-digit years are read and stored correctly.

SET EPOCH command allows you to set a date ranges of a 100 years that will be the basis SPSS uses for interpreting 2 digit year values entered into a date format variable. The default setting for EPOCH is 1900, the range being 1900 to 1999. You can use syntax to redefine the

100 year span.

1. If you use syntax to SET EPOCH to 1920, e. g.

SET EPOCH=1920.

The range for interpretation of 2 digit years will be 1920 to 2019. In this case, a two digit year enter of 01 would be interpreted as 2001.

2. If you use syntax to SET EPOCH to AUTOMATIC, e. g.

SET EPOCH=AUTOMATIC.

The Automatic setting for Epoch will use the system date to create the range. The lower bound of the range will be the current date minus 69. The upper bound of the range will be the current date plus 30. For example, in the year 2000, Automatic will create a range of 1931 though 2030.

If you would like to see the date range created by the SET EPOCH command that you use, type

SHOW EPOCH.

in a syntax window and it will return the setting and the range. This setting will remain in effect until it is reset with another SET EPOCH syntax command.

UKCC system administrator patched the SPSS 4.1 for MVS with the ZAP patch from the SPSS web site which made the MVS version of SPSS Y2K enabled. SET EPOCH command is not available on MVS. The MVS/SPSS software only supports the use and/or storage of four-digit year dates (which include the century) and it would be advisable for users to utilize these date formats in future data. For data that is already stored with two digit years SPSS on MVS will assume that the dates are from the 20th century. This means that data read into SPSS for MVS with two digit dates will be seen as 19xx dates. If the user would like to convert a previously stored date variable into a corrected century with a four digit year format then the following syntax could serve as an example for doing this.

EXAMPLE:

The user receives or creates a data set that has dates such as.

DATA LIST FREE /date (ADATE8).

BEGIN DATA

01/14/06

10/21/08

12/25/41

05/27/50

07/04/58

03/19/87

END DATA.

LIST.

If the user would like to be sure that the dates less than or equal to

"20" are converted as being in the 21st century (20xx) and those greater

than "20" are translated as being in the 20th century (19xx).

*The following syntax would accomplish this.

IF (XDATE.YEAR(date) <= 1920)

date2 = DATE.MDY( (XDATE.MONTH(date)) ,

(XDATE.MDAY(date)) , (XDATE.YEAR(date)+100)) .

IF (XDATE.YEAR(date) > 1920)

date2 = date.

EXECUTE .

FORMATS date2 (ADATE10).

If you have questions or need help, please contact SSTARS at 257-2204,

or sstars@pop.uky.edu.