| Main category | Number of variables | Variables |
| Study characteristics | 5 | Author |
|
|
| Publication year |
|
|
| Mean age of participants |
|
|
| L1 language for monolinguals |
|
|
| Languages for bilinguals |
| Research design | 2 | Group comparison |
|
|
| Linguistic development target |
| Outcome measure | 1 | Task type(s) |
| Effect size | 2 | Monolingual group size |
|
|
| Bilingual group size |