SPSS Binomial Logistic Regression Tutorial

An Interactive Tutorial for SPSS 10.0 for Windows©
Binomial Logistic Regression
by
Julia Hartman
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© Copyright 2000, Julia Hartman
1
Binomial Logistic Regression:
Introduction
According to SPSS Help, Logistic Regression:
…is useful for situations in which you want to be able to
predict the presence or absence of a characteristic or outcome
based on values of a set of predictor variables. It is similar to a
linear regression model but is suited to models where the
dependent variable is dichotomous. Logistic regression
coefficients can be used to estimate odds ratios for each of the
independent variables in the model.
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© Copyright 2000, Julia Hartman
2
Binomial Logistic Regression:
Introduction
This tutorial will use logistic regression to
determine if the year of matriculation, gender,
and US Medical Licensing Exam (Part 2) scores
be used to predict whether or not physicians are
board-certified in a primary care specialty
(Family Medicine, Internal Medicine, Pediatrics,
Ob-Gyn).
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3
Binomial Logistic Regression:
Introduction
• Independent variables (covariates)
 matyr: Matriculation year (continuous)
 gender: Gender of student (1 = female, 2 = male)
 usmle2: USMLE Step 2 (continuous)
• Dependent variable
 primcare: Board certified in Primary Care specialty
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4
Binomial Logistic Regression:
Starting the Procedure
• In the menu, click
Analyze
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5
Binomial Logistic Regression:
Starting the Procedure
• In the menu, click on
Analyze
• Point to
Regression
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6
Binomial Logistic Regression:
Starting the Procedure
• In the menu, click on
Analyze
• Point to
Regression
• Point to Binary Logistic…
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7
Binomial Logistic Regression:
Starting the Procedure
• In the menu, click on
Analyze
• Point to
Regression
• Point to Binary Logistic…
…and click.
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8
Binomial Logistic Regression:
Selecting Variables
Choose the variables
for analysis from the
list in the variable box.
Scroll down the list,
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9
Binomial Logistic Regression:
Selecting Variables
Choose the variables
for analysis from the
list in the variable box.
Scroll down the list,
point to primcare (the
dependent variable),
which is labeled
Board Certified in FM,
© Copyright 2000, Julia Hartman
10
Binomial Logistic Regression:
Selecting Variables
Choose the variables
for analysis from the
list in the variable box.
Scroll down the list,
point to primcare (the
dependent variable),
which is labeled
Board Certified in FM,
IM, Peds or Ob-Gyn
…and click.
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11
Binomial Logistic Regression:
Selecting Variables
Move primcare to the
box labeled
Dependent by
clicking the arrow.
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12
Binomial Logistic Regression:
Selecting Variables
Scroll back up the
variable list,
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13
Binomial Logistic Regression:
Selecting Variables
Scroll back up the
variable list,
point to
MATRICULATON DATE –
YEAR [matyr]
…and click.
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14
Binomial Logistic Regression:
Selecting Variables
Move matyr to the
box labeled
Covariates by
clicking the arrow.
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15
Binomial Logistic Regression:
Selecting Variables
Point to
GENDER OF STUDENT
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16
Binomial Logistic Regression:
Selecting Variables
Point to
GENDER OF STUDENT
[gender]
…and click.
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17
Binomial Logistic Regression:
Selecting Variables
Move gender to the
box labeled
Covariates by
clicking the arrow.
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18
Binomial Logistic Regression:
Selecting Variables
Scroll down the
variable list,
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19
Binomial Logistic Regression:
Selecting Variables
Scroll down the
variable list,
point to
USMLE STEP 2 TOTAL
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20
Binomial Logistic Regression:
Selecting Variables
Scroll down the
variable list,
point to
USMLE STEP 2 TOTAL
[usmle2]
…and click.
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21
Binomial Logistic Regression:
Selecting Variables
Move usmle2 to the
box labeled
Covariates by
clicking the arrow.
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22
Binomial Logistic Regression:
Categorical Variables
To designate
gender as a
categorical
variable, click the
button labeled
Categorical.
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23
Binomial Logistic Regression:
Categorical Variables
Click gender in the box
labeled Covariates
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24
Binomial Logistic Regression:
Categorical Variables
Click gender in the box
labeled Covariates,
then click the arrow to
move it to the box
labeled Categorical
Covariates.
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25
Binomial Logistic Regression:
Categorical Variables
Click the Continue
button.
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26
Binomial Logistic Regression:
Specifying Options
Specify options
by clicking the
button labeled
Options…
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27
Binomial Logistic Regression:
Specifying Options
Click the
checkbox for
Classification plots.
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28
Binomial Logistic Regression:
Specifying Options
In SPSS, you can
display information
by right-clicking,
but right-clicking
doesn’t work in this
tutorial.
To see what would
happen, left-click
the box for Hosmer-Lemeshow goodness-of-fit.
© Copyright 2000, Julia Hartman
29
Binomial Logistic Regression:
Specifying Options
For this tutorial,
click the checkbox
for
Hosmer-Lemeshow
goodness-of-fit.
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30
Binomial Logistic Regression:
Specifying Options
Click the Continue
button.
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31
Binomial Logistic Regression:
Selecting a Method of Entry
The covariates can be
entered into the analysis
using six different
methods. This tutorial
includes the Enter and
Forward: LR methods.
Choose one of the
following:
Click the printer for an important note
about printing output with
classification plots.
© Copyright 2000, Julia Hartman
• Enter
• Forward: LR
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Binomial Logistic Regression:
Enter Method
Enter is the default
method of entering
covariates.
Click the OK button
to run the procedure.
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33
Binomial Logistic Regression Output
Case Processing Summary
The labels and format
of your output may be
somewhat different.
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34
Binomial Logistic Regression Output
Variable Coding
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35
Binomial Logistic Regression Output (Enter Method)
Beginning Block: Classification Table
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36
Binomial Logistic Regression Output (Enter Method)
Beginning Block: Variables in the Equation
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37
Binomial Logistic Regression Output (Enter Method)
Chi-Square Tests of Coefficients
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38
Binomial Logistic Regression Output (Enter Method)
Model Summary
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39
Binomial Logistic Regression Output (Enter Method)
Hosmer-Lemeshow Contingency Table
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40
Binomial Logistic Regression Output (Enter Method)
Classification Table
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41
Binomial Logistic Regression Output (Enter Method)
Variables in the Equation
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42
Binomial Logistic Regression Output (Enter Method)
Classification Plot
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43
An Interactive Tutorial for
SPSS 10.0 for Windows©:
Binomial Logistic Regression
Choose one of the following:
• Repeat this tutorial
• Select the Forward: LR method of entry
• Return to the list of tutorials
© Copyright 2000, Julia Hartman
44
Binomial Logistic Regression:
Forward: LR Method
To select the Forward:
LR (Likelihood Ratio)
method of covariate
entry, click the dropdown arrow for
Method (next to Enter,
which is the default
method).
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45
Binomial Logistic Regression
Forward: LR Method
Point to
Forward: LR
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46
Binomial Logistic Regression
Forward: LR Method
Point to
Forward: LR
and click.
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47
Binomial Logistic Regression
Forward: LR Method
Click the OK
button to run
the procedure.
© Copyright 2000, Julia Hartman
48
Binomial Logistic Regression Output (Forward: LR Method)
Case Processing Summary
The labels and format
of your output may be
somewhat different.
Next
© Copyright 2000, Julia Hartman
49
Binomial Logistic Regression Output (Forward: LR Method)
Variable Coding
Next
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50
Binomial Logistic Regression Output (Forward: LR Method)
Beginning Block: Classification Table
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© Copyright 2000, Julia Hartman
51
Binomial Logistic Regression Output (Forward: LR Method)
Beginning Block: Variables in the Equation
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52
Binomial Logistic Regression Output (Forward: LR Method)
Chi-Square Tests of Coefficients
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53
Binomial Logistic Regression Output (Forward: LR Method)
Model Summary
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54
Binomial Logistic Regression Output (Forward: LR Method)
Hosmer-Lemeshow Contingency Table
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55
Binomial Logistic Regression Output (Forward: LR Method)
Hosmer-Lemeshow Contingency Table
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56
Binomial Logistic Regression Output (Forward: LR Method)
Hosmer-Lemeshow Contingency Table
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57
Binomial Logistic Regression Output (Forward: LR Method)
Classification Table
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58
Binomial Logistic Regression Output (Forward: LR Method)
Variables in the Equation
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Binomial Logistic Regression Output (Forward: LR Method)
Model if Term Removed
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Binomial Logistic Regression Output (Forward: LR Method)
Variables not in the Equation
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61
Binomial Logistic Regression Output (Forward: LR Method)
Classification Plot for Step 1
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62
Binomial Logistic Regression Output (Forward: LR Method)
Classification Plot for Step 2
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63
Binomial Logistic Regression Output (Forward: LR Method)
Classification Plot for Step 3
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© Copyright 2000, Julia Hartman
64
An Interactive Tutorial for
SPSS 10.0 for Windows©:
Binomial Logistic Regression
Click one of the following:
• Repeat this tutorial
• Select the Enter method of entry
• Return to the list of tutorials
© Copyright 2000, Julia Hartman
65
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
SPSS WILL CRASH if you try to print logistic
regression output which includes classification plots.
• You can avoid this problem by printing the output in
two parts. Click the
button to learn how.
• For more information, click the link below:
http://www.spss.com/tech/answer/result.cfm?tech_tan_id=100007850
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© Copyright 2000, Julia Hartman
66
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
The classification plot(s)
must be printed separately
from the rest of the output.
In SPSS, you would begin
by right-clicking the plot,
but right-clicking doesn’t
work in this tutorial.
Click the classification
plot.
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67
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Right-clicking opens
the shortcut menu.
• Click SPSS Rtf
Document Object.
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68
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Right-clicking opens
the shortcut menu.
• Click SPSS Rtf
Document Object.
• Then point to
Open
© Copyright 2000, Julia Hartman
69
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Right-clicking opens
the shortcut menu.
• Point to
SPSS Rtf
Document Object.
• Then point to
Open
…and click
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70
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Print the plot from
this new window.
• Click File
This output file has
been saved as
logistic (enter 3).spo
Your window will be
different.
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71
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Print the plot from this new
window.
• Click File
• Then point to Print
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72
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Print the plot from this new
window.
• Click File
• Then point to Print
• Click to print the plot
Of course, the plot won’t
print from this tutorial!
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73
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Close the window.
• Click File
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74
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Close the window.
• Click File
• Then click
Exit & Return to (the file
name--in this example)
logistic (enter 3).spo
Next
© Copyright 2000, Julia Hartman
75
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
In SPSS you would
delete the classification
plot (still selected) by
pressing the delete key,
but that won’t work in
this tutorial.
Next
© Copyright 2000, Julia Hartman
76
Binomial Logistic Regression Output (Forward: LR Method)
Printing Logistic Regression Output
Print the rest of the output
as usual, either from the
File menu or by clicking
the print button
on the toolbar.
Remember, you can’t print from
the tutorial.
Next
© Copyright 2000, Julia Hartman
77
An Interactive Tutorial for
SPSS 10.0 for Windows©:
Binomial Logistic Regression
Choose one of the following:
• Resume this tutorial
• Repeat this tutorial
• Return to the list of tutorials
© Copyright 2000, Julia Hartman
78