title: Response to Marschner's letter to the editor.
authors.affiliation: Harvard Medical School, Boston, MA 02115, USA fitzmaur@hsph.harvard.edu.
authors.forename: Garrett M
authors.initials: GM
authors.lastname: Fitzmaurice
authors.affiliation: Brigham and Women's Hospital, Boston, MA 02115, USA.
authors.forename: Stuart R
authors.initials: SR
authors.lastname: Lipsitz
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D015233:Models, Statistical; D012044:Regression Analysis; D012306:Risk