On Warning Symbols, Text, and ‘getting it right’: The Iterative Refinement of a Teratogenic Pharmaceutical Label

Abstract

Several birth defects warning symbols identified as most successful in an earlier study (Mayhorn & Goldsworthy, 2007) were further modified and then evaluated within a nationally distributed field trial (n = 2773). A total of 11 warning labels were examined: 4 new symbols plus the existing baseline symbol, each in versions with and without text, plus a text-only condition. Participant interpretation accuracy and preferences were assessed. For symbol-only conditions, several candidate symbols outperformed the existing symbol, one substantially so. The effect of adding text to symbols varied significantly by symbol. Symbol+text and text-only conditions performed equivalently, generally exceeded symbol-only conditions, and often surpassed the ANSI benchmark of 85% accurate interpretation. Implications are drawn from the process and outcomes in relation to warning design, warning evaluation, and future research.