title: Sample selection.
authors.affiliation: Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115, USA.
authors.forename: J
authors.initials: J
authors.lastname: Orav
mesh_terms: D016001:Confidence Intervals; D006302:Health Services Research / Q000379:methods*; D006801:Humans; D018579:Patient Selection; D011897:Random Allocation; D012107:Research Design; D015983:Selection Bias