Table 1.4 Levels of Evidence
| Level | Research Design | Description |
| Level 1a | Randomized Controlled Trial (RCT) | More than 1 RCT with PEDro score ≥6.
Includes within subjects comparison with randomized conditions and crossover designs. |
| Level 1b | RCT | 1 RCT with PEDro ≥6. |
| Level 2 | RCT | RCT, PEDro <6. |
| PCT | Prospective controlled trial (not randomized). | |
| Cohort | Prospective longitudinal study using at least two similar groups with one exposed to a particular condition. | |
| Level 3 | Case Control | A retrospective study comparing conditions including historical controls. |
| Level 4 | Pre-Post test | A prospective trial with a baseline measure, intervention, and a post- test using a single group of subjects. |
| Post-test | A prospective intervention study using a post intervention measure only (no pre-test or baseline measurement) with one or more groups | |
| Case Series | A retrospective study usually collecting variables from a chart review. | |
| Level 5 | Observational Study | Using cross sectional analysis to interpret relations |
| Clinical Consensus | Expert opinion without explicit critical appraisal, or based on physiology, biomechanics or “first principles”. | |
| Case Reports | Pre-post or case series involving one subject. |