Table 2. Comprehension scores by study group.

Comprehension score (range)	Intervention group	Control group	P value
Overall comprehension score (0 – 4)	Parent (P): 3.6 (0.7)-----Youth (Y): 2.7 (1.1)	P: 2.9 (0.9)-----Y: 1.7 (1.1)	< 0.0001----- < 0.0001
Nature of procedure (0 – 4)	P: 3 (0.9)-----Y: 2.9 (1.1)	P: 3 (0.7)-----Y: 2.4 (0.9)	0.6-----0.02
Benefits of procedure (0 – 1)	P: 1 (0)-----Y: 0.8 (0.4)	P: 1 (0.2)-----Y: 0.8 (0.4)	0.16-----0.77
Risks of procedures (0 – 3)	P: 2.8 (0.5)-----Y: 2.5 (0.8)	P: 1.2 (1.0)-----Y: 0.6 (0.9)	< 0.0001----- < 0.0001
Alternatives to procedure (0 – 1)	P: 0.7 (0.5)-----Y: 0.2 (0.4)	P: 0.4 (0.5)-----Y: 0.2 (0.4)	< 0.004-----0.16

Results expressed as mean (standard deviation). Youth = Child (7 – 12 years) and Adolescent (13 – 17 years).