Tag Archives: Longitudinal data

Recommended: Bayesian computing with INLA

This page promotes a new approach to a broad class of models (spatio-temporal models, latent variable models, mixed models) using a fast approximation to the Bayesian solution. It runs under R and appears to handle very large datasets. I have not had a chance to try this, but it looks very interesting. Continue reading

PMean: Simple longitudinal data sets to illustrate data management

I am working on a class that will teach basic data management and graphics using the R programming language with parallel classes in SPSS and SAS. On the third or fourth day of the class, we will look at managing longitudinal data sets, as these require special skills. I wanted to find a couple of reasonably simple longitudinal data sets that were available on the web and which had at least a few missing values in them. Here’s a couple of data sets that might work. Continue reading

Recommended: Comparisons within randomised groups can be very misleading

In studies with a baseline, examining the decline exclusively within the treated group, or examining the decline in the treated group and then separately examining the decline in the control group is a bad idea, notes two famous statisticians in the British Medical Journal. They explain why you need to look first at comparisons between the two groups, ideally with analysis of covariance. Continue reading