title: Sources of error in clinical research.
authors.affiliation: Clinical Epidemiology Unit, King George's Medical College, Lucknow.
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: S
authors.initials: S
authors.lastname: Kumar
mesh_terms: D000704:Analysis of Variance; D015982:Bias; D015986:Confounding Factors, Epidemiologic; D006801:Humans; D011336:Probability; D012044:Regression Analysis; D012106:Research / Q000706:statistics & numerical data*; D012107:Research Design; D015983:Selection Bias