# random effect

### How to Produce Intercepts if the Random Slope Model Produces a Variance Estimate, Not Coefficients

August 14th, 2017 by

In this video I will answer a question from a recent webinar Random Intercept and Random Slope Models.

We are answering questions here because we had over 500 people live on the webinar so we didn’t have time to get through all the questions.

If you missed the webinar live, this and the other questions in this video series may make more sense if you watch that first. It was part of our free webinar series, The Craft of Statistical Analysis, and you can sign up to get the free recording, handout, and data set at this link:

http://TheCraftofStatisticalAnalysis.com/random-intercept-random-slope-models

### Is a Random Intercept Different in Each Treatment Group?

August 11th, 2017 by

In this video I will answer a question from a recent webinar Random Intercept and Random Slope Models.

We are answering questions here because we had over 500 people live on the webinar so we didn’t have time to get through all the questions.

If you missed the webinar live, this and the other questions in this series may make more sense if you watch that first. It was part of our free webinar series, The Craft of Statistical Analysis, and you can sign up to get the free recording, handout, and data set at this link:

http://TheCraftofStatisticalAnalysis.com/random-intercept-random-slope-models

### Mixed Models: Can you specify a predictor as both fixed and random?

February 16th, 2016 by

One of the most confusing things about mixed models arises from the way it’s coded in most statistical software.  Of the ones I’ve used, only HLM sets it up differently and so this doesn’t apply.

But for the rest of them—SPSS, SAS, R’s lme and lmer, and Stata, the basic syntax requires the same pieces of information.

1.       The dependent variable

2.       The predictor variables for which to calculate fixed effects and whether those (more…)

### Why Mixed Models are Harder in Repeated Measures Designs: G-Side and R-Side Modeling

February 25th, 2015 by

I have recently worked with two clients who were running generalized linear mixed models in SPSS.

Both had repeated measures experiments with a binary outcome.

The details of the designs were quite different, of course. But both had pretty complicated combinations of within-subjects factors.

Fortunately, both clients are intelligent, have a good background in statistical modeling, and are willing to do the work to learn how to do this. So in both cases, we made a lot of progress in just a couple meetings.

I found it interesting, through, that both were getting stuck on the same subtle point. It’s the same point I was missing for a long time in my own learning of mixed models.

Once I finally got it, a huge light bulb turned on. (more…)