This document discusses different types of study designs used in research. It outlines observational studies like case reports, case series, cross-sectional studies and case-control studies which collect data without intervening. Experimental studies like randomized controlled trials where participants are randomly allocated to intervention and comparison groups are also discussed. The key factors in choosing a suitable study design are whether the research question requires an intervention, comparison group and following subjects over time. Study designs must be matched to the research question regarding prevalence, etiology, prognosis or effects of therapy.
6. Case
Reports
or Series Describes case
characteristics
May generate future ideas
Useful for rare diseases and if
disease is caused by single
kind of exposure
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11. Case Control Studies
Identifying a group of subjects defined by their
outcome, we look back in time to identify an
exposure of interest.
The aim is to identify risk factors of disease
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15. Cohort Study
Identifying a group of subjects defined by their
exposure status, being followed up over time to
identify an outcome of interest.
The aim is to determine whether an exposure status
influences risk of disease
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Research
Question
Prevalence
Etiology & risk factors
Diagnosis: signs,
symptoms or tests
Prognosis
Therapy
Study Design
Cross-sectional study
Cohort study/ Case–
control
RCT or cross sectional
Cohort study
RCT
