Year: 1992 Source: American Journal of Epidemiology, v.135, no.11, (June 1, 1992), p.1310-1314 SIEC No: 19920701

In this letter to the editor, the authors comment on an article by Gibbons et al (see SIEC #901360). They raise 4 points about the way in which the statistical analysis was done. The reply of Gibbons & his colleagues to these concerns follows.