Symbols were superior to numbers for presenting strength of recommendations to health care consumers: a randomized trial.
OBJECTIVE
To compare health care consumers' understanding, evaluations, and preferences for symbols vs. numbers and letters for the representation of strength of recommendations (SOR) and quality of evidence (QOE).


METHODS
Questionnaire study in a randomized controlled design in the setting of a community health education program.


RESULTS
Eighty-four participants completed the questionnaire. For the presentation of the SOR, participants had better objective understanding of symbols than numbers (74% vs. 14%, P<0.001). They also scored symbols positively, and numbers negatively for ease of understanding (mean difference [md]=1.5, P=0.001), clearness and conciseness (md=1.5, P<0.001), and conveyance of the degree of uncertainty (md=0.7, P=0.092). About half (48%) preferred symbols over numbers. For the presentation of the QOE, objective understanding of symbols and letters was similar (91% vs. 95%, P=0.509). Participants scored both symbols and letters positively; the scores for symbols were however lower for ease of understanding (md=-0.7, P=0.019), clearness and conciseness (md=-0.6, P=0.051), and conveyance of the QOE (md=-0.4, P=0.24).


CONCLUSIONS
Symbols were superior to numbers for the presentation of the SOR. Objective understanding was high for both symbols and letters for the presentation of the QOE, but letters conveyed the QOE better than symbols.
Akl
Elie A
EA
Department of Medicine, University at Buffalo, NY, USA.
Maroun
Nancy
N
Guyatt
Gordon
G
Oxman
Andrew D
AD
Alonso-Coello
Pablo
P
Vist
Gunn E
GE
Devereaux
P J
PJ
Montori
Victor M
VM
Schünemann
Holger J
HJ
D000328:Adult; D000368:Aged; D003142:Communication; D003153:Community Health Services / Q000379:methods; D032882:Comprehension; D003258:Consumer Behavior; D019317:Evidence-Based Medicine; D005260:Female; D006266:Health Education / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015397:Program Evaluation; D011795:Surveys and Questionnaires