Download NURS 802- Epidemiology * Source of Bias Lori Lemoine

NURS 802- Epidemiology – Source of Bias
Identify the type of bias (information or selection bias) in the following examples, and indicate if
this bias would shift the value more towards the null, or away from the null.
1
What bias would you suspect in a study to determine the prevalence of disability in the state’s
elderly population, based on a survey of members in a social club for seniors?
Bias: __Selection – social club would have fewer disabled elderly_____
Result: Toward null__X___ Away from null ______
2
What bias would you suspect in a community survey of mental illness in which 30% of the
study sample refused to be interviewed or examined?
Bias: _Selection as it creates a response bias__________________________
Result: Toward null__x___ Away from null ______
3
What kind of bias would you suspect in a survey to determine the prevalence of diabetes,
based on the single question, “Has a doctor ever told you that you have diabetes?”
Bias: _Selection via response bias, Recall bias- as maybe they can not recall being dx
and have been, Misclassification as they are not diabetic and were told that they
were_______________________________
Result: Toward null__X___ Away from null _X__--depends on the bias actually
occurring as response and misclassification would be towards null and recall away
4
What bias would you expect in a survey of the prevalence of illicit drug use by face-to-face
interviews?
Bias: Interviewer bias________________________________
Result: Toward null____ Away from null ___x___
5
What bias would you suspect in a survey of the prevalence of cigarette smoking, based on
questions put to people who had just been exposed to an intensive antismoking program?
Bias: __Interviewer bias ___________________________
Result: Toward null_____ Away from null ___x___
6
What bias could you expect in a study of the incidence of headaches in a population where
your subjects used daily diaries to record the symptoms they experienced, day by day for one
month.
Bias: ___Misclassification bias as may thought they experienced more HA than
normal______________________
Result: Toward null_____ Away from null __x____
7
To study the incidence of impotence as a side-effect of drug treatment for hypertension,
patients were questioned about impotence after a year of being on treatment. They were not
told the reason for asking the question on impotence.
Bias: _Misclassification bias or recall bias_______________________________
Result: Toward null__x___ Away from null ______
8
In a similar study, patients were questioned about impotence and were told that the drug they
took had a potential side effect of impotence.
Bias: _Recall bias- may blame impotence on meds_________________________
Result: Toward null_____ Away from null _x__