SPSS® 12.0 Command Syntax Reference

ROC
Overview
Options
ROC varlist BY varname({varvalue })
{‘varvalue’}
[/MISSING = {EXCLUDE**}]
{INCLUDE }
[/CRITERIA = [CUTOFF({INCLUDE**})] [TESTPOS({LARGE**}) [CI({95**})]
{EXCLUDE } {SMALL } {value}
[DISTRIBUTION({FREE** })]]
{NEGEXPO}
[/PLOT = [CURVE**[(REFERENCE)]] [NONE]]
[/PRINT = [SE] [COORDINATES]].
** Default if subcommand is omitted.
ROC produces a receiver operating characteristic (ROC) curve and an estimate of the area
under the curve.
Distributional Assumptions. In the CRITERIA subcommand, the user can choose the nonparametric
or parametric method to estimate the standard error of the area under the curve.
Currently, the bi-negative exponential distribution is the only parametric option.
Optional Output. In addition to an estimate of the area under the ROC curve, the user may
request its standard error, a confidence interval, and a p value under the null hypothesis that
the area under the curve equals 0.5. A table of cutoff values and coordinates used to plot the
ROC curve may also be displayed.
Basic Specification
The basic specification is one variable as the test result variable and one variable as the
actual state variable with one of its values. ROC uses the nonparametric (distribution-free)
method to calculate the area under the ROC curve. The default and minimum output is a
chart of the ROC curve and a table of the area under the curve.
Syntax Rules
• Minimum syntax: You always need a test result variable and one actual state variable
with one of its values in the ROC command line.
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