title: Coping with extra poisson variability in the analysis of factors influencing vaginal ring expulsions.
authors.forename: C G
authors.initials: CG
authors.lastname: Demétrio
authors.forename: M S
authors.initials: MS
authors.lastname: Ridout
mesh_terms: D003274:Contraceptive Devices, Female / Q000706:statistics & numerical data*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D016014:Linear Models; D016012:Poisson Distribution; D012044:Regression Analysis; D014621:Vagina