SPSS® 12.0 Command Syntax Reference

VARIABLES Subcommand
COXREG 297
VARIABLES identifies the dependent variable and the covariates to be included in the analysis.
• The minimum specification is the dependent variable. The subcommand keyword is optional.
• Cases whose dependent variable values are negative are excluded from the analysis.
• You must specify the keyword WITH and a list of all covariates if no METHOD subcommand
is specified or if a METHOD subcommand is specified without naming the variables
to be used.
• If the covariate list is not specified on VARIABLES but one or more METHOD subcommands
are used, the covariate list is assumed to be the union of the sets of variables listed
on all the METHOD subcommands.
• You can specify an interaction of two or more covariates using the keyword BY. For
example, A B BY C D specifies the three terms A, B*C, and D.
• The keyword TO can be used to specify a list of covariates. The implied variable order is
the same as in the working data file.
STATUS Subcommand
To determine whether the event has occurred for a particular observation, COXREG checks
the value of a status variable. STATUS lists the status variable and the code for the occurrence
of the event.
• Only one status variable can be specified. If multiple STATUS subcommands are specified,
COXREG uses the last specification and displays a warning.
• The keyword EVENT is optional, but the value list in parentheses must be specified.
• The value list must be enclosed in parentheses. All cases with non-negative times that do
not have a code within the range specified after EVENT are classified as censored cases—
that is, cases for which the event has not yet occurred.
• The value list can be one value, a list of values separated by blanks or commas, a range
of values using the keyword THRU, or a combination.
• If missing values occur within the specified ranges, they are ignored if MISSING=EXCLUDE
(the default) is specified, but they are treated as valid values for the range if MISSING=INCLUDE
is specified.
• The status variable can be either numeric or string. If a string variable is specified, the
EVENT values must be enclosed in apostrophes and the keyword THRU cannot be used.
Example
COXREG SURVIVAL WITH GROUP
/STATUS SURVSTA (3 THRU 5, 8 THRU 10).
• STATUS specifies that SURVSTA is the status variable.
• A value between either 3 and 5, or 8 and 10, inclusive, means that the terminal event
occurred.
• Values outside the specified ranges indicate censored cases.