A three-stage model summarizes product warning and environmental sign research

The past 25 years have experienced a substantial amount of research on safety communications, more specifically, warnings. This article focuses on the most important factors in designing effective warnings. The warning process is modeled in three stages. Effective warnings attract attention; elicit knowledge, and enable compliance behavior. Two main categories are design factors and non-design factors. Non- design factors include the effects of target audience and situational factors. For attention, important design factors are size, color/contrast, signal word, graphics, and format. The non-design factors for atten- tion include context, location, and distraction. Design factors affecting the knowledge and compliance stages include explicit wording and pictorials to provide hazard, consequences and instructional content. Non-design factors for the knowledge stage include familiarity and perceived hazard. Non-design factors for the compliance stage include modeling the behavior of others and cost of compliance. The research literature offers practical design recommendations to aid application decisions. Ó 2011 Elsevier Ltd. All rights reserved.