Flashcards in Lecture 5: Bias & Misclassification Deck (33)
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1
what 3 aspects of a study, must researchers evaluate for internal validity before they can declare a true association?
1. confounders and effect modifiers
2. bias and misclassification
3. statistical significance
2
definition of bias
systematic error in study design or conduct, resulting in false results
3
how do we control for bias after a study has been conducted?
we can't
must be done before study is implemented
4
what are the 3 elements of bias impact?
1. source or type
2. magnitude
3. direction
5
the 2 main categories of bias
selection-related
measurement-related
6
selection-related bias
any aspect in the way the researcher selects study subjects differently
7
measurement-related bias
any aspect in the way the researcher collects data differently
8
types of selection bias
healthy-worker bias
self-selection bias
9
other names for responder bias
self-selection bias
participant bias
10
what type of bias is easily seen in prospective cohort studies?
healthy-worker bias
11
measurement bias can be ……?
subject related
observer related
screening related
12
subject related bias
type of measurement bias
recall bias
hawthorne effect
contamination bias
compliance bias
lost to follow up bias
13
groups being studied have different withdrawal rates
lost to follow up bias
14
groups being interventionally studied have different adherence with study protocols
compliance/adherence bias
15
members of the control group, receive treatment or are exposed to the intervention being studied
contamination bias
take drugs they shouldn't
16
individuals alter their behavior because they know they are apart of a study under observation
hawthorne effect
or
observer effect
17
a differential level of accuracy in provided information between study groups
recall bias or reporting bias
18
observer-related
type of measurement bias
interviewer bias
surveillance bias
19
a systematic difference in interpreting done by the researcher
interviewer bias
not always consciously done
20
different evaluation or diagnosis between study groups due to an observers expectations
diagnosis/surveillance/expectation bias
21
screening-related
type of measurement bias
lead-time bias
22
an apparent benefit from a healthcare screening due to the early detection of disease despite an unchanged clinical outcome
lead-time bias
23
source of measurement bias, especially observer-related bias
misclassification bias
24
error in classifying either disease or exposure status, or both
misclassification
25
the 2 types of misclassification
differential
non-differential
26
misclassification of exposure which is unrelated to the other exposure
non-differential = error in both groups equally
27
not different
non-differential
28
in non-differential bias, the measure of association is always....?
type of misclassification
OR is always moved towards 1.0
29
misclassification of exposure which is related to the other exposure
differential misclassification
30
in differential bias, the measure of association is.....?
can be inflated or depreciated
31
ways to control for bias
blinding/masking
multiple data sources
randomly allocate observers for data collection
minimize loss to follow up bias
32
random allocation and randomization are ways to control for....?
random = bias control
randomization = confounding control
33
