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Flashcards in Categorical data II Deck (10)
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1

Give examples of prospective studies

cohort studies
longitudinal studies
follow-up studies

2

Describe prospective studies

identify individuals with relevant characteristics then follow over time and record eventual outcomes

3

What are caveats for observational studies?

Only able to demonstrate associations between exposure and outcome, rather than causal relationship. A confounding factor may be related to both exposure and outcome seperately

4

Describe cohort studies

most ideal form of observational study
analogous to a clinical trial (without randomisation)
can follow the natural history of disease in time, from exposure to outcomes
Loss to follow up - connected to outcome is problem
Change in exposure / risk over time

5

How is the relative risk calculated?

(a/a+c)/(b/b+d)

6

How are confidence intervals calculated for RR?

logeRR +/- 1.96/SE(logeRR)

7

Describe hypothesis testing for RR

Ho is that RR=1
z = logeRR/SE(logeRR)

8

Describe case-control studies

quicker and cheaper if outcome is rare
selection of controls and matching are issues
recall accuracy

9

Describe the odds ratio

cannot use RR for case-control studies because cases and controls are fixed by study design
OR=ad/bc

10

How is the OR calculated for matched controls?

OR=b/c