SDIFF Subcommand (PPLOT command)

If the variable exhibits a seasonal or periodic pattern, you can use the SDIFF subcommand to seasonally difference the variable before plotting.

• The specification on SDIFF indicates the degree of seasonal differencing and can be any positive integer.
• If SDIFF is specified without a value, the degree of seasonal differencing defaults to 1.
• The number of plotted seasons decreases by 1 for each degree of seasonal differencing.
• The length of the period that is used by SDIFF is specified on the PERIOD subcommand. If the PERIOD subcommand is not specified, the periodicity that is established on the TSET or DATE command is used (see PERIOD Subcommand (PPLOT command)).