Design | Types of groups | Literature grade | Tier |
---|---|---|---|
Meta-analysis | Â | 1 | 1 |
Systematic or integrative review of literature | Â | 1 | |
Experimental | Between subjects (experimental and control) | 2 | |
 | Within subjects (cross-over) | 2 | |
Quasi-experimental | Non-equivalent control group | 3 | 2 |
 | Repeated measures | 3 | |
Pre-experimental | Comparison group | 4 | |
 | Pre-test/post-test | 4 | |
 | Post-test only | 5 | |
Descriptive studies | Retrospective | 6 | 3 |
 | Case series, correlation | 6 | |
 | Prospective/cross-sectional | 6 | |
 | Literature review (descriptive) | 6 | |
Qualitative studies | Â | 7 |