Logistic Regression

How to Get SPSS GENLINMIXED Output Without the Model Viewer

September 26th, 2014 by

I love working with my clients.

I love working with my clients for many reasons, but one of them is I learn so much from them.

Just this week, one of my clients showed me how to get SPSS GENLINMIXED results without the Model Viewer.

She’s my new hero.

If you’ve ever used GENLINMIXED, the procedure for Generalized Linear Mixed Models, you know that the results automatically appear in this new Model Viewer.  (more…)


Generalized Linear Models in R, Part 3: Plotting Predicted Probabilities

July 2nd, 2014 by

In our last article, we learned about model fit in Generalized Linear Models on binary data using the glm() command. We continue with the same glm on the mtcars data set (regressing the vs variable on the weight and engine displacement).

Now we want to plot our model, along with the observed data.

Although we ran a model with multiple predictors, it can help interpretation to plot the predicted probability that vs=1 against each predictor separately.  So first we fit a glm for only (more…)


Generalized Linear Models in R, Part 2: Understanding Model Fit in Logistic Regression Output

June 24th, 2014 by

In the last article, we saw how to create a simple Generalized Linear Model on binary data using the glm() command. We continue with the same glm on the mtcars data set (more…)


Generalized Linear Models in R, Part 1: Calculating Predicted Probability in Binary Logistic Regression

June 18th, 2014 by

Ordinary Least Squares regression provides linear models of continuous variables. However, much data of interest to statisticians and researchers are not continuous and so other methods must be used to create useful predictive models.

The glm() command is designed to perform generalized linear models (regressions) on binary outcome data, count data, probability data, proportion data and many other data types.

In this blog post, we explore the use of R’s glm() command on one such data type. Let’s take a look at a simple example where we model binary data.

(more…)


SPSS Procedures for Logistic Regression

May 15th, 2014 by

Need to run a logistic regression in SPSS? Turns out, SPSS has a number of procedures for running different types of logistic regression.

Some types of logistic regression can be run in more than one procedure.  For some unknown reason, some procedures produce output others don’t.  So it’s helpful to be able to use more than one.

Logistic Regression

SPSS Binary Logistic Regression MenuLogistic Regression can be used only for binary dependent (more…)


Specifying a Random Intercept or Random Slope Model in SPSS GENLINMIXED

September 13th, 2013 by

One of the things I love about MIXED in SPSS is that the syntax is very similar to GLM.  So anyone who is used to the GLM syntax has just a short jump to learn writing MIXED.

Which is a good thing, because many of the concepts are a big jump.

And because the MIXED dialogue menus are seriously unintuitive, I’ve concluded you’re much better off using syntax.

I was very happy a few years ago when, with version 19, SPSS finally introduced generalized linear mixed models so SPSS users could finally run logistic regression or count models on clustered data.

But then I tried it, and the menus are even less intuitive than in MIXED.

And the syntax isn’t much better.  In this case, the syntax structure is quite different than for MIXED. (more…)