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25 Cards in this Set
- Front
- Back
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stats and epi show what?
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associations
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stats are good at showing ___ but bad at shoing ___?
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chance; bias
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two situations that lead to false associations?
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multiple comparisons and disease clusters
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multiple comparisons and disease clusters are examples of what?
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ad hoc application of stats
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if rr is <1, was disease reduced?
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yes
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if ci includes 1, is this statistically significant?
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no
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third variables ethat are linked to exposure and outcome?
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confounding factors
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systematic error that gets into a study and is one sided?
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bias
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ultimate way to deal with bias? confounding?
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blinding; randomization
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confounder must be linked to ___ and ___
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exposure and disease
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examples of observational studies? interventional/experimental studies?
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case control and cohort studies; clinical trials
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cohort study?
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start with disease free; can be prospective or retrospective
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cohort studies won't work if disease is ___
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rare
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in retrospective, do some people have disease or are they all disease free?
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some have disease
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problems with retrospective study?
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confounding factors
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a and d or cohort studies?
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a: little bias, establish rr, ethics and standard of care can prevent others
d: expensive, continued exposure, takes a long time |
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case control study?
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take cases and controls and look back to see if there were any exposure differences
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can you calculate incidence in a case control study? prevalence?
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no; no
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what do you calculate in a case control study?
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odds ratio
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what do you calculate in a cohort study?
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rr
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a and d of case control study?
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a: cheap, easy, good for rare disease
d: bias, bad if exposure is rare, no info on incidence |
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when do you do a nested case control study?
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when the study is too expensive or difficult
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what is nesteed case control study?
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start with disease free; sample all who develop disease as cases and some who don't for later use as controls
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rr formula?
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(a/a+b)/(c/c+d)
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odds ratio formula?
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ad/bc
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