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  #1  
Old 08-13-2011
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Default bias 2 cases

case 1 0f 2


A doctors wants to analyze the effectiveness of using mammogram to screen for breast cancer. In her analysis, she compares the disease-free survival rate in patients screened using mammogram to the disease-free survival rate in patients diagnosed with breast ca prior to screening with mammogram . She concludes that screening is effective with mammogram , because the disease-free survival rate is higher in screened patients compared to unscreened patients.An oncologist reviews these findings and the epidemiologist's conclusions. He argues that her conclusions are incorrect, because improved survival rates following screening programs are the result of treating less aggressive tumors, not because of the screening program itself. The oncologist is arguing what type of bias has occurred in the epidemiologist's findings?
A. Lead-time bias
B. Length-time bias
C. Overdiagnosis bias
D. Recall bias
E. Selection bias



case 2 0f 2

A doctors is attempting to characterize the link between smoking and bladder ca in a large population. He plans to use a large paper-based questionnaire that will be randomly mass mailed to approximately 10,000 individuals. In the questionnaire, there are numerous questions on alcohol and smoking use, current health issues, and socioeconomic indicators. The questionnaire will need to be mailed back to the epidemiologist and he will provide all individuals with a self-addressed stamped envelope to facilitate this process. What type of bias is this study most likely to suffer from?

A. Compliance bias
B. Lead-time bias
C. Overdiagnosis bias
D. Publication bias
E. Selection bias
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  #2  
Old 08-13-2011
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if i had to guess on the first one I would say A...lead time....
Second one is non Compliance..
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Old 08-13-2011
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Originally Posted by Kais_MD View Post
if i had to guess on the first one I would say A...lead time....
Second one is non Compliance..
no wrong
same mistake i did in 1st q
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Old 08-13-2011
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Originally Posted by miss patho View Post
no wrong
same mistake i did in 1st q
overdiagnosis bias..<<<havent heard of it.....if not definitly selection bias lol....cuz it makes more sense in which age group they are in too..
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Old 08-13-2011
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for first maybe selection bias. second i don;t know what;s publication bias?
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nothing is impossible!
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  #6  
Old 08-14-2011
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Originally Posted by miss patho View Post
case 1 0f 2


A doctors wants to analyze the effectiveness of using mammogram to screen for breast cancer. In her analysis, she compares the disease-free survival rate in patients screened using mammogram to the disease-free survival rate in patients diagnosed with breast ca prior to screening with mammogram . She concludes that screening is effective with mammogram , because the disease-free survival rate is higher in screened patients compared to unscreened patients.An oncologist reviews these findings and the epidemiologist's conclusions. He argues that her conclusions are incorrect, because improved survival rates following screening programs are the result of treating less aggressive tumors, not because of the screening program itself. The oncologist is arguing what type of bias has occurred in the epidemiologist's findings?
A. Lead-time bias
B. Length-time bias
C. Overdiagnosis bias
D. Recall bias
E. Selection bias



case 2 0f 2

A doctors is attempting to characterize the link between smoking and bladder ca in a large population. He plans to use a large paper-based questionnaire that will be randomly mass mailed to approximately 10,000 individuals. In the questionnaire, there are numerous questions on alcohol and smoking use, current health issues, and socioeconomic indicators. The questionnaire will need to be mailed back to the epidemiologist and he will provide all individuals with a self-addressed stamped envelope to facilitate this process. What type of bias is this study most likely to suffer from?

A. Compliance bias
B. Lead-time bias
C. Overdiagnosis bias
D. Publication bias
E. Selection bias

1st case the correct answer is B. Length-time bias

2nd case the correct answer is E. Selection bias
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  #7  
Old 08-14-2011
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Originally Posted by Kais_MD View Post
overdiagnosis bias..<<<havent heard of it.....if not definitly selection bias lol....cuz it makes more sense in which age group they are in too..
overdiagnosis bias is observer bias ididnt hear about it bf but q mention it
and 2nd one u r right
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