POPH192 Lecture 26 - Information Bias

Question 1

what is information bias?

Answer 1

observation or information bias results from systematic differences in the way data on exposure or outcome are obtained from the various study groups

Question 2

how can measurement error occur?

Answer 2

• participants provide inaccurate responses by under or overestimating their exposure
• data is collected incorrectly/inaccurately by the person collecting data in a different procedure

Question 3

what are the 2 types of measurement error?

Answer 3

1) random

2) systematic

Question 4

what effect might measurement error have in a descriptive study?

Answer 4

could lead to underestimate or overestimate of the prevalence

Question 5

what effect might measurement error have in an analytic study?

Answer 5

can lead to misclassification

Question 6

what is non-differential misclassification?

Answer 6

when measurement error and any resulting misclassification occurs equally in all groups being compared
-estimate moves towards the null value

Question 7

what is an example of differential misclassification in a cross-sectional study?

Answer 7

in a cross-sectional study people with the outcome might report the exposure differently to those without the outcome

Question 8

what is an example of differential misclassification in a case-control study?

Answer 8

in a case-control study, cases might more accurately recall past exposure compared to controls

Question 9

what is recall bias?

Answer 9

systematic error due to differences in accuracy or completeness of recall to memory of past events or experiences

Question 10

what are the 3 steps to consider bias is present?

Answer 10

1) who does it affect?
2) how does it affect them?
3) what effect does this have on the measure of association?`