Data analysis

All data were analysed using Microsoft Access and Excel by the staff at NCEPOD. The data were aggregated before review by the NCEPOD clinical co-ordinators and advisors.

During the course of the study, large amounts of data were collected about many different aspects of the management of AAA. Analysis of these data has focused on providing descriptive statistical analyses. No attempt has been made to carry out formal statistical hypothesis testing and hence no p-values are presented. This is because the study was not designed with a priori hypotheses in mind. Also if significance testing were to be carried out for every analysis provided, then correcting for multiple comparison on such a large scale would render all results insignificant. On the other hand, retrospectively to choose a small number of analyses to subject to hypothesis testing would not be scientifically valid.