Jeromy Anglim's Blog: Psychology and Statistics

Wednesday, November 26, 2008

Longitudinal Data with Varying Numbers of Time Points using SPSS

I recently chatted with a researcher who had data in the following format: around 20 participants; participants completed between 5 and 15 sessions, but some sessions involved missing data and sessions could be classified into one of five phases. For each session there were a few measurements. There were also a number of baseline measures. The challenge was how to make the most of the data file. The following were a few recommendations I made.

Thursday, November 20, 2008

Carryover Effects in Repeated Measures Designs

This post discusses the issue of carryover effects in repeated measures designs. Ways of assessing and dealing with carryover effects are discussed. I then apply the concepts to an example from my own research looking at personality faking.

Wednesday, November 12, 2008

Causality and Mediation Analysis

This post discusses issues with causal inference in mediation analysis. It proposes a set of steps that researchers can use when analysing and reporting mediation analyses.

Friday, November 7, 2008

Using R to test for significant differences between two nonindependent correlations

I was recently asked about a quick and easy way to see whether the correlation between IV1 and DV is statistically significantly different from IV2 and DV. The follow post set out how this analysis can be conducted in R. The instructions assume that you have never used R before and are running Windows.

Getting Started with Mediation and Moderation: SPSS and R Resources

The following post sets out resources for getting started with mediation and moderation analysis.

First Post

Okay. So this is the first post.
I'm hoping that this blog will be useful to others.
In particular I do a fair amount of statistical consulting to psychology and other social science researchers.
I figured this could be a place to maintain answers to common and not so common questions.

I'm also a big fan of R ( I'm keen to share some of the little tricks that I've learnt over the while in how to learn and get the most out of R.

I also plan to brainstorm various ideas in relation to my various research interests, which currently tend to be associated with industrial / organisational psychology and social network analysis.

Anyway, we'll see how it evolves over time.