The Comprehensibility and Legibility of Twenty Pharmaceutical Warning Pictograms

Abstract

The purpose of the reported three phase study was to test the comprehensibility and legibility of twenty prescription warning labels that were likely to have adverse effects if taken incorrectly and to redesign those that were poorly understood. The underlying message or warning did not achieve an eighty-five percent comprehension level in sixteen of the twenty pictorials. Through an analysis of errors made by first phase participants and the incorporation of common elements suggested by a diverse focus group, ten of the pictorials were redesigned. Comparisons between pre- and post-redesign comprehensibility revealed significant improvements for eight of the ten labels for a younger test sample and three of ten for an elderly sample. Participants also indicated that they preferred the redesigned labels. Discussions center on pharmaceutical pictogram design guidelines and comprehension standards.