Summary

On reading the study report (Romney et al., 2005) it was decided to question the adequacy of two of these approaches to the statistical analysis and to examine whether a more rigorous treatment of the data would lead to the same or a different interpretation. This is the primary focus of this case study.

Difficulties arose in the handling the large amounts of data that were collected. Data management and editing aspects arising from longitudinal studies are discussed. The programming attributes of GenStat are also illustrated in the statistical analysis.

Finally the importance of being able to critically review a scientific publication, and not to necessarily take the authors' statistical analyses and conclusions at their face value, is emphasised.