The DROPEVENT statement specifies that some event variables be excluded from the OUTEVENT= data set. As a result, the DROPEVENT statement is valid only for data files containing event-oriented time series data. All the BY variables, the time ID variable DATE, and the event-grouping variable EVENT are always included in the OUTEVENT= data set. These variables cannot be referenced in the DROPEVENT statement. If any of these variables are referenced, a warning message is given and the reference is ignored.

The variable list can contain variable names or name range specifications. See Variable Lists for details.

Only one DROPEVENT or one KEEPEVENT statement can be used. DROPEVENT and KEEPEVENT are mutually exclusive.

You can also use the DROP= data set option to control which event variables to exclude from the OUTEVENT= data set. However, the DROPEVENT statement differs from the DROP= data set option in several respects:

• The DROPEVENT statement selection is applied before variables are read from the data file, while the DROP= data set option selection is applied after variables are read and as they are written to the OUTEVENT= data set. Therefore, using the DROPEVENT statement instead of the DROP= data set option is much more efficient.

• If the DROPEVENT statement causes all series variables to be excluded, then no observations are output to the OUTEVENT= data set.