Department of Medical Statistics, Leiden University Medical Center, The Netherlands. j.j.goeman@lumc.nl|Department of Medical Statistics, Leiden University Medical Center, The Netherlands. j.j.goeman@lumc.nl|Department of Medical Statistics, Leiden University Medical Center, The Netherlands. j.j.goeman@lumc.nl|Department of Medical Statistics, Leiden University Medical Center, The Netherlands. j.j.goeman@lumc.nl|Department of Medical Statistics, Leiden University Medical Center, The Netherlands. j.j.goeman@lumc.nl