Observational studies
- Cross sectional study (prevalence)
- Case control study
- Cohort study
Advantages of Randomised Controlled Trial (RCT)
- Evaluation of single variable
- Prospective study
- Reduces bias
- Allows for meta-analysis
Hierarchy of evidence
- Case report
- Cross sectional study
- Case control study
- Cohort study
- Randomised controlled trial
- Systematic review & meta-analysis