Table 2.

Predicted effects with 95% confidence intervals from mixed effects analyses for categorical moderators including unpublished studies

	k	N	r̄	95% CI	QM	p	R2
Gestational Age					0.2	.91	.00
Very preterm	4	326	−.15	−.43, .13
Moderate preterm	15	3,516	−.16	−.24, −.08
Term	6	3,299,845	−.13	−.23, −.03
Geographic Region					34.7	<.0001	.22
South America	3	4,112	−.04	−.07, −.01
Asia	5	873	−.27	−.49, −.06
Australia & New Zealand	7	5,881	−.13	−.21, −.05
Europe	31	4,477,464	−.13	−.16, −.11
North America	37	120,440	−.15	−.18, −.11
ADHD measure					35.5	<.0001	.11
Medical record	15	4,542,862	−.14	−.17, −.10
Interview	14	9,262	−.21	−.29, −.13
Questionnaire	50	55,665	−.11	−.13, −.08
Multiple methods	6	2,158	−.25	−.43, −.07
Informant					9.9	.04	.24
Parent	47	146,703	−.13	−.15, −.10
Clinician	14	4,455,284	−.15	−.18, −.11
Teacher	6	3,396	−.13	−.19, −.08
Multiple	15	3,912	−.18	−.29, −.07
Self	3	652	−.13	−.44, −.17
Age					0.2	.98	.00
3–5.9 years	13	20,071	−.14	−.19, −.08
6–8.9 years	30	21,436	−.16	−.21, −.11
9–12.9 years	17	4,406	−.15	−.23, −.07
13–20 years	12	8,113	−.16	−.24 −.08
Birth Weight
Ascertainment					0.5	.49	.19
Parental report	26	128,760	−.15	−.18, −.12
Medical or birth record	48	4,474,495	−.13	−.15, −.10
Sample Type					43.4	<.0001	.05
ADHD based	16	6,376	−.18	−.27, −.08
Birth Weight based	40	8,546	−.20	−.24, −.15
Community based	17	18,678	−.06	−.09, −.04
Population based	12	4,576,347	−.09	−.12, −.06
Birth Weight					5.6	.06	.20
Very low birth weight	4	310	−.09	−.30, .11
Low birth weight	21	5,009	−.20	−.28, −.13
Normal birth weight	21	11,803	−.11	−.16, −.06

Note. CI=confidence interval. P-values derived from tests of heterogeneity examining the amount of variability explained by each moderator variable.