Troubleshooting
Problem
Can SPSS compute Youden's index, which can be expressed as sensitivity + specificity -1?
Resolving The Problem
Below are commands to produce a table with sensitivity, specificity and Youden's index. Comments are included that indicate how you might edit for your particular situation. These commands will work for either a situation where multiple values of a test variable are being assessed via an ROC curve, or where the variables forming a single 2x2 table are input to the procedure.
*Make sure your current data file has been saved before running these commands.
*Change the file name from C:\temp\ROC.sav if desired.
OMS
/SELECT TABLES
/IF COMMANDS = ["ROC Curve"]
SUBTYPES = ["Coordinates of the Curve"]
/DESTINATION FORMAT = SAV
OUTFILE = "C:\temp\ROC.sav".
OMS
/SELECT ALL
/IF COMMANDS = ["ROC Curve"]
/DESTINATION VIEWER = NO.
*Change the test and outcome variable names if necessary, and/or the value of the
*outcome value. If the outcome of interest has a smaller value than the negative
*outcome, change "LARGE" to "SMALL" on the CRITERIA subcommand. If you
*want the cutoff value excluded, change "INCLUDE" to "EXCLUDE" on the
*CRITERIA subcommand.
ROC testvar BY statevar (1)
/CRITERIA = TESTPOS(LARGE) CUTOFF(INCLUDE)
/PRINT = COORDINATES.
OMSEND.
*If you changed the file name or path above, change it here to match.
GET FILE = "C:\temp\ROC.sav".
SELECT IF Sensitivity NE @1Specificity.
COMPUTE Specificity = 1 - @1Specificity.
COMPUTE Youden = Sensitivity - @1Specificity.
FORMATS Specificity Youden (F8.3).
*If you changed LARGE to SMALL, change "Greater" in the first variable name on
*the TABLES subcommand to "Less". If you changed INCLUDE to EXCLUDE,
*remove "orEqualTo" from the end of that variable name.
SUMMARIZE
/TABLES=PositiveifGreaterThanorEqualTo Sensitivity Specificity Youden
/FORMAT=LIST NOCASENUM
/TITLE="Sensitivity, Specificity & Youden's Index"
/CELLS=NONE.
Related Information
Historical Number
59162
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Document Information
Modified date:
16 April 2020
UID
swg21477309