| Comparative non-randomized | Comparative AND randomized | Survey or questionnaire | Descriptive experience | Expert opinion, editorial or comment | Systematic review and meta-analysis | Narrative review |
---|---|---|---|---|---|---|---|
Number of studies | 32 | 16 | 45 | 21 | 5 | 4 | 1 |
Sample sizea | 162 [20–1707] | 121 [31–1649] | 124 [14–569] | 73 [16–561] | - | 1652 [1003–2061] | - |
Main outcomes | |||||||
 Performance | 21 | 14 | 10 | 6 | 1 | 3 | 1 |
 Knowledge retention | 5 | 2 | 4 | 3 | - | 1 | - |
 Student satisfaction | 6 | - | 25 | 5 | - | - | - |
 Tutor satisfaction | - | - | 4 | 1 | 1 | - | - |
 Not specified | - | - | - | 5 | 3 | - | - |
 Other | - | - | 2 | 1 | - | - | - |
Secondary outcomes | |||||||
 Knowledge retention | 3 | - | 1 | 1 | - | - | - |
 Student satisfaction | 6 | 7 | 5 | 4 | - | 1 | 1 |
 Tutor satisfaction | 1 | - | 5 | 3 | - | - | - |
 Social and/or communication skills | 1 | - | 3 | 1 | - | - | - |
 Reasoning | - | - | - | 1 | - | - | - |
 Other | 2 | 1 | - | - | - | 1 | - |
Continent | |||||||
 Asia | 6 | 8 | 22 | 5 | - | 4 | - |
 North America | 16 | 2 | 10 | 9 | 1 | - | 1 |
 Europe | 4 | 5 | 7 | 3 | 3 | - | - |
 Africa | 2 | - | 3 | 2 | - | - | - |
 Oceania | 1 | 1 | 2 | 1 | 1 | - | - |
 South America | 3 | - | 1 | 1 | - | - | - |