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Bias
Question | Answer |
---|---|
Selection Bias | Nonrandom assignment to study groups(Berkson's Bias) |
Recall Bias | Knowledge of presence of disorder alters recall by subjects. |
Sampling Bias | Subjects are not representative relative to general population; therefore, results are not generalizable. |
Late-Look Bias | Information gathered at inappropriate time. |
Procedure Bias | Subjects in different groups are not treated the same. |
Confounding Bias | Occurs with 2 closely associated factors; the effect of 1 factor distorts or confuses the effect of the other. |
Lead-time Bias | Early detection confused with increased survival; seen with improved screening (natural history of disease is not changed, but early detection makes it seem as though survival increases). |
Pygmalion effect | Occurs when a researcher's belief in the efficacy of a treatment changes the outcome of that treatment. |
Hawthorne effect | Occurs when the group being studied changes its behavior owing to the knowledge of being studied. |