Final answer:
Studies are classified based on the level of evidence. The levels range from systematic reviews and meta-analyses to expert opinions.
Step-by-step explanation:
The classification of studies based on the level of evidence is as follows:
- Level 1: Systematic review and meta-analysis
- Level 2: Randomized controlled trial (RCT) or Experimental study
- Level 3: Quasi-experimental study
- Level 4: Mixed-methods systematic review and qualitative meta-synthesis
- Level 5: Descriptive correlational, predictive correlational, and cohort studies
- Level 6: Descriptive study and qualitative study
- Level 7: Opinions of expert committees and authorities