Regression Tutorial

© Copyright 2000, Julia Hartman © Copyright 2000, Julia Hartman 11

An Interactive Tutorial for SPSS 10.0 for Windows©

by

Julia Hartman

Binomial Logistic Regression

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Binomial Logistic Regression:Binomial Logistic Regression:

IntroductionIntroduction

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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.




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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• 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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Starting the ProcedureStarting the Procedure

• In the menu, clickAnalyze


Binomial Logistic Regression: Binomial Logistic Regression:


• In the menu, click onAnalyze

• Point to Regression




• Point to Binary Logistic…





…and click.


• Point to Binary Logistic…





Selecting VariablesSelecting Variables

Choose the variables for analysis from the list in the variable box.

Scroll down the list,





Scroll down the list, point to primcare (the dependent variable), which is labeledBoard Certified in FM,





…and click.

Scroll down the list, point to primcare (the dependent variable), which is labeledBoard Certified in FM, IM, Peds or Ob-Gyn




Move primcare to the box labeledDependent by clicking the arrow.




Scroll back up the variable list,




Scroll back up the variable list, point toMATRICULATON DATE – YEAR [matyr]

…and click.




Move matyr to the box labeled

Covariates by clicking the arrow.




Point to GENDER OF STUDENT




…and click.

Point to GENDER OF STUDENT [gender]




Move gender to the box labeled

Covariates by clicking the arrow.




Scroll down the variable list,




Scroll down the variable list, point toUSMLE STEP 2 TOTAL




…and click.

Scroll down the variable list, point toUSMLE STEP 2 TOTAL [usmle2]




Move usmle2 to the box labeled Covariates by clicking the arrow.



Categorical VariablesCategorical Variables

To designate gender as a categorical variable, click the button labeled Categorical.




Click gender in the box labeled Covariates




Click gender in the box labeled Covariates, then click the arrow to move it to the box labeled Categorical

Covariates.




Click the Continue button.



Specifying OptionsSpecifying Options

Specify options by clicking the button labeledOptions…




Click the checkbox for Classification plots.


In SPSS, you can display information by right-clicking, but right-clicking doesn’t work in this tutorial.

To see what wouldhappen, left-click the box for Hosmer-Lemeshow goodness-of-fit.






For this tutorial, click the checkbox forHosmer-Lemeshow goodness-of-fit.




Click the Continue button.


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:


Selecting a Method of EntrySelecting a Method of Entry

• Enter

• Forward: LR

Click the printer for an important note about printing output with

classification plots.


Enter is the default method of entering covariates.

Click the OK button to run the procedure.


Enter MethodEnter Method


Binomial Logistic Regression Output Binomial Logistic Regression Output

Case Processing SummaryCase Processing Summary

The labels and format of your output may be somewhat different.

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Binomial Logistic Regression Output Binomial Logistic Regression Output

Variable CodingVariable Coding

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Binomial Logistic Regression Output (Enter Method)Binomial Logistic Regression Output (Enter Method)

Beginning Block: Classification TableBeginning Block: Classification Table

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Beginning Block: Variables in the EquationBeginning Block: Variables in the Equation

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Chi-Square Tests of CoefficientsChi-Square Tests of Coefficients

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Model SummaryModel Summary

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Hosmer-Lemeshow Contingency TableHosmer-Lemeshow Contingency Table

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Classification TableClassification Table

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Variables in the EquationVariables in the Equation

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Classification PlotClassification Plot

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• Return to the list of tutorials

An Interactive Tutorial for An Interactive Tutorial for SPSS 10.0 for WindowsSPSS 10.0 for Windows©©::

Binomial Logistic RegressionBinomial Logistic Regression

• Repeat this tutorial


• Select the Forward: LR method of entry



Forward: LR MethodForward: LR Method

To select the Forward: LR (Likelihood Ratio) method of covariate entry, click the drop-down arrow for Method (next to Enter, which is the default method).




Point to Forward: LR




Point to Forward: LR and click.




Click the OK button to run the procedure.


Binomial Logistic Regression Output (Forward: LR Method)Binomial Logistic Regression Output (Forward: LR Method)

Case Processing SummaryCase Processing Summary

The labels and format of your output may be somewhat different.

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Variable CodingVariable Coding

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Beginning Block: Classification TableBeginning Block: Classification Table

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Beginning Block: Variables in the EquationBeginning Block: Variables in the Equation

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Chi-Square Tests of CoefficientsChi-Square Tests of Coefficients

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Model SummaryModel Summary

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Variables in the EquationVariables in the Equation

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Model if Term RemovedModel if Term Removed

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Variables not in the EquationVariables not in the Equation

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Classification Plot for Step 1Classification Plot for Step 1

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Click one of the following:

• Select the Enter method of entry



Printing Logistic Regression OutputPrinting Logistic Regression Output

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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




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.




Right-clicking opens the shortcut menu.

• Click SPSS Rtf Document Object.





• Click SPSS Rtf Document Object.

• Then point toOpen





• Point toSPSS Rtf Document Object.

• Then point toOpen

…and click




Print the plot from this new window.

• Click File

This output file has been saved aslogistic (enter 3).spoYour window will be different.




Print the plot from this new window.• Click File

• Then point to Print




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!




Close the window.

• Click File




Close the window.

• Click File

• Then click

Exit & Return to (the file name--in this example)logistic (enter 3).spo

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In SPSS you would delete the classification plot (still selected) by pressing the delete key, but that won’t work in this tutorial.

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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.


• Resume this tutorial






Regression Tutorial

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