Table 1.
Overview of covariates for educational achievement (Eindtoets Basisonderwijs test scores) that were used in the application.
| N | |
|---|---|
| Sex | |
| Boy | 992 (50.10 %) |
| Girl | 988 (49.90 %) |
| School size | 1447 (73.08 %) |
| Missing | 533 (26.92 %) |
| Pedagogical philosophy | |
| Regular education | 1467 (74.09 %) |
| Dalton | 41 (2.10 %) |
| Jenaplan | 12 (0.61 %) |
| Montessori | 21 (1.06 %) |
| Specialised regular education | 16 (0.81 %) |
| Specialised education | 6 (0.30 %) |
| Missing | 417 (21.10 %) |
| Denomination of school | |
| Protestant-Christian (PC) | 332 (16.77 %) |
| Reformed | 22 (1.11 %) |
| Reformed liberated | 8 (0.40 %) |
| Roman-Catholic (RC) | 606 (30.61 %) |
| Collaboration of PC & RC | 10 (0.51 %) |
| Special | 59 (2.98 %) |
| State | 461 (23.28 %) |
| Missing | 482 (24.34 %) |
N = total number of individual twins