| Model | Study Name | Comparison | Outcome | Statistics for each study | Sample size | |||
|---|---|---|---|---|---|---|---|---|
| Hedges's g | Lower limit | Upper limit | Group A | Group B |
||||
| Ryan (1964) | parent_vs_control | Combined | 0.347 | 0.088 | 0.605 | 5 | 5 | |
| Aronson (1966) | Combined | Read_Ach | 1.109 | 0.421 | 1.798 | 18 | 18 | |
| Clegg (1971) | Combined | Combined | 0.776 | -0.098 | 1.651 | 10 | 10 | |
| Hirst (1974) | parent_vs_control | Combined | 0.181 | -0.217 | 0.579 | 48 | 48 | |
| Henry (1974) | Combined | Combined | 0.281 | -0.677 | 1.239 | 7 | 11 | |
| O'Neil (1975) | Combined | Combined | 0.223 | -0.724 | 1.169 | 7 | 9 | |
| Tizard (1982) | Combined | Read_Comp | 0.879 | 0.369 | 1.390 | 26 | 43 | |
| Heller (1993) | parentrpt_vs_control | Combined | 1.496 | 0.881 | 2.110 | 26 | 26 | |
| Miller (1993) | Combined | Combined | 0.164 | -0.557 | 0.884 | 16 | 13 | |
| Roeder (1993) | parent_vs_control | Math_Ach | 0.123 | -0.445 | 0.692 | 23 | 23 | |
| Fantuzzo (1995) | Combined | Combined | 0.741 | -0.047 | 1.529 | 13 | 13 | |
| Ellis (1996) | parent_vs_control | Combined | -0.116 | -0.652 | 0.420 | 20 | 38 | |
| Joy (1996) | Combined | Cr_Math_Ach | 0.114 | -0.842 | 1.071 | 10 | 9 | |
| Peeples (1996) | parent_vs_control | Combined | 0.920 | 0.345 | 1.495 | 25 | 25 | |
| Kosten (1997) | parent_vs_control | Science_Ach | 0.075 | -0.573 | 0.723 | 17 | 18 | |
| Hewison (1988) | Combined | Read_Comp | 0.646 | 0.089 | 1.203 | 21 | 35 | |
| Meteyer (1998) | parent_vs_control | Combined | 0.381 | -0.164 | 0.925 | 25 | 27 | |
| Powell-Smith (2000) | Combined | Combined | -0.298 | -1.076 | 0.480 | 12 | 12 | |
| Fixed | 0.430 | 0.299 | 0.561 | |||||
| Random | 0.453 | 0.248 | 0.659 | |||||
| Heterogeneity Statistics for a Fixed Effect Model: Q = 35.6, df = 17, p = 0.005, and I squared = 52.3 | ||||||||