Hi Pat
If you are using multiple logistic regression, then you have to save
the predicted values as a new variable and then, as someone else has
suggested, run ROC analysis. You will get sensitivity and false
positive rate. False negative rate and specificity can be easily
obtained by substraction.
The following example computes sensitivity & 1-specificity (=false
positive rate) for a simple logistic regression model, but the process
is similar for multiple regression models:
* Dataset from Hosmer&Lemeshow's Applied Logistic Regression *.
DATA LIST FREE/ age chd (2 F8.0).
BEGIN DATA
20 0 23 0 24 0 25 0 25 1 26 0 26 0 28 0 28 0 29 0
30 0 30 0 30 0 30 0 30 0 30 1 32 0 32 0 33 0 33 0
34 0 34 0 34 1 34 0 34 0 35 0 35 0 36 0 36 1 36 0
37 0 37 1 37 0 38 0 38 0 39 0 39 1 40 0 40 1 41 0
41 0 42 0 42 0 42 0 42 1 43 0 43 0 43 1 44 0 44 0
44 1 44 1 45 0 45 1 46 0 46 1 47 0 47 0 47 1 48 0
48 1 48 1 49 0 49 0 49 1 50 0 50 1 51 0 52 0 52 1
53 1 53 1 54 1 55 0 55 1 55 1 56 1 56 1 56 1 57 0
57 0 57 1 57 1 57 1 57 1 58 0 58 1 58 1 59 1 59 1
60 0 60 1 61 1 62 1 62 1 63 1 64 0 64 1 65 1 69 1
END DATA.
VAR LABELS age 'Age at follow-up start'
/chd 'Coronary Heart Disease'.
VALUE LABELS chd 0 'Absent' 1 'Present'.
LOGISTIC REGRESSION chd
/METHOD = ENTER age
/SAVE = PRED (predict).
ROC predict BY chd (1)
/PLOT = CURVE
/PRINT = SE
/CRITERIA = CUTOFF(INCLUDE) TESTPOS(LARGE) DISTRIBUTION(FREE) CI(95)
/MISSING = EXCLUDE .
PC> A colleague and I are performing logistic regressions. He's using SAS and
PC> I'm using SPSS.
PC> I've been able to match up all my SPSS output with his SAS output, except
PC> that the SAS output contains a table that shows the Sensitivity,
PC> Specificity, % False Negative and % False Positive for each probability
PC> level. Is it possible to generate this table in SPSS? I've looked at the
PC> documentation for LOGISTIC REGRESSION and don't see an option that will do
PC> it. Alternatively, is it available as part of another analysis?
-----
Regards,
Dr. Marta García-Granero,PhD mailto:
[hidden email]
Statistician
---
"It is unwise to use a statistical procedure whose use one does
not understand. SPSS syntax guide cannot supply this knowledge, and it
is certainly no substitute for the basic understanding of statistics
and statistical thinking that is essential for the wise choice of
methods and the correct interpretation of their results".
(Adapted from WinPepi manual - I'm sure Joe Abrahmson will not mind)
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