Table 2. Readability data for 91 research information leaflets used in biomedical research studies, classified by age of the intended reader.

Readability characteristics	Child 6–11 y (group A)	Adolescent 12–17 y (group B)	Child and adolescent 6–17 y (group C)	Common RIL for Parents/Child (group D)
Number of RIL, n (%)	15 (16%)	20 (22%)	37 (41%)	19 (21%)
RIL with illustration, n (%)	7 (47%)	5 (25%)	1(3%)	0
Text length in words, median [25th; 75th percentiles]	607 [464; 869]	1225 [784; 1819]	456 [292; 706]	1134 [836; 1429]
Flesch score, median [25th; 75th percentiles]	46 [38; 52]	40 [30; 47]	37 [27; 43]	25 [22; 28]

Text length and Flesch score also differed significantly between the 4 groups (p<0.001).