| Categories | Characteristic | No. of peers | No. de articles |
| Diagnosis | Typical development | 449 (93.8%) | 65 (92.8%) |
| Atypical development | 30 (6.2%) | 3 (4.3%) | |
| Age | 2 and 3 |
| 9 (12.8%) |
| 4 and 5 |
| 17 (24.3%) | |
| 6 and 7 |
| 8 (11.4%) | |
| 8 up to 11 |
| 11 (15.8%) | |
| 12 up to 17 | 21 (30%) | ||
| 18 or more | 4 (5.7%) | ||
| Not reported | 20 (28.6%) | ||
| Gender | Male | 164 (34.2%) | 41 (58.6%) |
| Female | 184 (38.4%) | 41 (58.6%) 23 (32.8%) | |
| Not reported | 131 (27.3%) | ||
| Number of peers per participants | Up to 5 |
| 23 (32.8%) |
| 6 or more |
| 36 (51.4%) | |
| Not reported |
| 11 (15.7%) |