title: [Limitations of observation].
authors.affiliation: Leids Universitair Medisch Centrum, afd. Klinische Epidemiologie, Leiden. j.p.vandenbroucke@lumc.nl
authors.forename: Jan P
authors.initials: JP
authors.lastname: Vandenbroucke
mesh_terms: D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D019370:Observation; D010051:Ovarian Neoplasms / Q000601:surgery / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D012107:Research Design