SPSS® 12.0 Command Syntax Reference

ROC 1443
• The test result variable must be numeric, but the state variable can be any type with any
format.
• Subcommands can be specified in any order.
• When a subcommand is duplicated, only the last one is honored given that all duplicates
have no syntax errors. A syntax warning is issued.
• Within a subcommand, if two or more exclusive or contradictory keywords are given, the
latter keywords override the earlier ones. A syntax warning is issued.
• If a keyword is duplicated within a subcommand, it is silently ignored.
Limitations
Example
• Only the nonparametric method and one parametric method are available as the computational
options for the standard error of the area under the curve at this moment. In the
future, binormal and bilogistic distributions may be added to the parametric option.
ROC
pred BY default (1)
/PLOT = CURVE
/CRITERIA = CUTOFF(INCLUDE) TESTPOS(LARGE)
DISTRIBUTION(FREE) CI(95)
/MISSING = EXCLUDE .
• pred is the test result variable, and default is the actual state variable. The “positive” group
is identified by the value 1.
• The PLOT subcommand specifies that the ROC curve chart should be displayed without
the diagonal reference line.
• CRITERIA specifies that classification of values of the test result variable as members of
the “positive” group includes values greater than or equal to the cutoff values, the standard
error of the area under the curve is to be estimated nonparametrically, and the confidence
level for the asymptotic interval for the area under the curve is 95.
• MISSING specifies that both user-missing and system-missing values are excluded.
• No optional table output is printed.
varlist BY varname(varvalue)
The varlist specifies one or more test result variables. They must be of numeric type.
The varname separated from the varlist by the word BY specifies the actual state variable.
It can be of any type and any format. The user must also specify a varvalue in brackets after
the second varname to define the “positive” group of the actual state variable. All other valid
state values are assumed to indicate the negative group.