MARK Subcommand (TSPLOT command)

MARK indicates the onset of an intervention variable.

• The onset date is indicated by a vertical reference line.
• The specification on MARK can be either a variable name or an onset date if the DATE_ variable exists.
• If a variable is named, the plot indicates where the values of that variable change.
• A date specification follows the same format as the DATE command; that is, a keyword followed by a value. For example, the specification for June 1955 is Y 1955 M 6 (or Y 55 M 6 if only the last two digits of the year are used on DATE).

The following figure shows a plot with January 2001 marked as the onset date.

Figure 1. MARK=Y 2001 M 1