HSCI 330 Lecture Notes - Lecture 4: Relative Risk, Clinical Trial, Observational Error
8 Mar 2017
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Document Summary
Each shot: represents an estimate of the true effect obtained from one of possibly many studies in each of three populations. The validity of an epidemiologic study concerns whether or not there are imperfections in the study design, the methods of data collection, or the methods of data analysis that might distort the conclusion make about an exposure-disease relationship. If yes, the extent of the distortion of conclusions about an exposure-disease relationship (effect measure) bias. Risk ratio in sample= 1. 2 = true rr in source population= 1. 2 valid. Failure to take into account additional variables (beach: age, sex, duration ) 2 different sources of inaccuracy: validity problem: Systematic error**: a difference between what an estimator is actually estimating and the effect measure of interest bias (impossible to quantify but direction) (between study population and source population) Does not consider statistic inference but rather methodologic imperfections of the study design or analysis: precision problem: random error.
