SPSS® 12.0 Command Syntax Reference

1474 Syntax Reference
Subcommand Order
Syntax Rules
Operations
Limitations
Example
• By default, SEASON uses a multiplicative model to compute and display moving averages,
ratios, seasonal factors, the seasonally adjusted series, the smoothed trend-cycle components,
and the irregular (error) component for each series (variable) specified. The default
periodicity is the periodicity established on TSET or DATE.
• Unless the default on TSET NEWVAR is changed prior to the procedure, SEASON creates
four new variables for each series specified: SAF#n to contain the seasonal adjustment
factors, SAS#n to contain the seasonally adjusted series, STC#n to contain the smoothed
trend-cycle components, and ERR#n to contain the irregular (error) component. These
variables are automatically named, labeled, and added to the working data file. (For variable
naming and labeling conventions, see “New Variables” on p. 1734.)
• Subcommands can be specified in any order.
• VARIABLES can be specified only once.
• Other subcommands can be specified more than once, but only the last specification of
each one is executed.
• The endpoints of the moving averages and ratios are displayed as system-missing in the
output.
• Missing values are not allowed anywhere in the series. (You can use the RMV command
to replace missing values, and USE to ignore missing observations at the beginning or end
of a series. See RMV and USE in the SPSS Syntax Reference Guide for more information.)
• Maximum 1 VARIABLES subcommand. There is no limit on the number of series named
on the list.
SEASON VARX
/MODEL=ADDITIVE
/MA=EQUAL.
• In this example, an additive model is specified for the decomposition of VARX.
• The moving average will be computed using the EQUAL method.