12. CE: Bias, Chance, Confounding Flashcards
A study is examining diet of men over 60 years old. Men who eat fast food >5 days a week have an increased risk of having a MI. The associated risk increases by 15% if these men drink alcohol 5 days or more a week. In this study fast food and alcohol are examples of which of the following?
A. Confounding variable B. Effect modification C. Berkson's Bias D. Overdiagnosis E. Hawthorne Effect
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Ans B Effect Modification
Effect modification means there is an interaction between both factors in question. Eating fast food and drinking alcohol 5 days a week together increases the risk of MI more than just eating fast food alone.
A study of 100 Americans age 30 examined the accuracy of event recall. Subjects were interviewed and asked to recall events during the summer of 1997. Data was collected via interview. Photographs and reports from the participants’ parents were collected as evidence of events. It was found that participants were able to recall moments best if they were traumatizing in nature. For example, a man was able to describe how he nearly drowned in the lake in July 1997. Another woman stated the details of being bit by the neighbor’s dog. The results of this study are an example of ________?
A. Response Bias B. Interviewer Bias C. Berkson's Bias D. Recall Bias E. Rosenthal Effect
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Ans D Recall Bias
Recall bias occurs when data is skewed the further the respondent gets from the actual event. Differing emotional states can cause recall bias. The events of drowning or being attacked by a dog are very emotional and will be remembered more vividly than pleasant, mundane, non emotional events.
A normally very lazy undergrad signs up for a research study for some extra cash. He typically sits slumped over and often rests his head in his hands. During the study, he is placed in a room with a two way mirror and told that there are researchers watching on the other side when in reality, there are not. He sits more upright and has his hands folded on the table as he awaits instructions. This is an example of what? (MG)
A. Berkson’s Bias
B. Hawthorne Effect
C. Pygmalion Effect
D. Rosenthal Effect
B. Hawthorne Effect
His behavior is changed bc he believes he is being watched, even though he is not.
FYI Pygmalion and Rosenthal Effects are the same thing.
Man-Ray is running a clinical trial. He is observing the link between exposure to cigarette smoke and incidences of lung cancer. At the end of the trial, he decides to include hookah smoke, since both are tobacco based forms of smoking. What type of bias has he committed? (MG)
A. This is not a type of bias
B. Transfer bias
C. Outcome Misclassification
D. Exposure misclassification
D. Exposure misclassification
He is using a proxy of exposure. Researchers need to clearly define the exposure they will be examining in a study.
