study design.pdf aimed at learning for studies

Study guide

17. Strengths
Relatively quick, cheap and easy to conduct (no long periods of follow-up).
Data on all variables is only collected once.
Able to measure prevalence for all factors under investigation.
Multiple outcomes and exposures can be studied.
The prevalence of disease or other health-related characteristics are important
in public health for assessing the burden of disease in a specified population
and in planning and allocating health resources.
Good for descriptive analyses and for generating hypotheses.

18. Weaknesses
Difficult to determine whether the exposure or outcome came first (“Association and
Causation”)
Not suitable for studying rare diseases or diseases with a short duration.
As cross-sectional studies measure prevalent rather than incident
Associations identified may be difficult to interpret.
Susceptible to biases

23. Strengths
Cost-effective relative to other analytical studies such as cohort studies.
Case-control studies are retrospective, cases are identified at the beginning of the study
therefore there is no long follow-up period (compared to cohort studies).
Efficient for the study of diseases with long latency periods.
Efficient for the study of rare diseases.
Good for examining multiple exposures simultaneously

24. Weaknesses
Particularly prone to bias; especially selection, recall and observer bias.
Unable to estimate incidence rates of disease
Poor choice for the study of rare exposures.(diagnostic)
.

30. Strengths
Multiple outcomes can be measured for any one exposure.
Can look at multiple exposures.
Exposure is measured before the onset of disease (in prospective cohort studies) i.e. the
temporal relationship is certain.
Demonstrates direction of causality.
Good for measuring rare exposures, for example among different occupations.
Good for outcomes which occur long after exposure
Can measure incidence and prevalence.

31. Weaknesses
Costly and time consuming.
Prone to bias due to loss to follow-up.
Being in the study may alter participant behavior.
Inefficient for the study of a rare disease outcome.