The comment relating R to Stata, SAS and SPSS is now on the Burns Statistics website at http://www.burns-stat.com/pages/Tutor/R_relative_statpack.pdf And also on the UCLA website where the original technical report can be found as well. http://www.ats.ucla.edu/stat/technicalreports/ Thank you to all who contributed comments. Patrick Burns patrick at burns-stat.com +44 (0)20 8525 0696 http://www.burns-stat.com (home of S Poetry and "A Guide for the Unwilling S User")