Communicating infectious disease prevalence through graphics: Results from an international survey

BACKGROUND: Graphics are increasingly used to represent the spread of infectious diseases (e.g., influenza, Zika, Ebola); however, the impact of using graphics to adequately inform the general population is unknown. OBJECTIVE: To examine whether three ways of visually presenting data (heat map, dot map, or picto-trendline)—all depicting the same information regarding the spread of a hypothetical outbreak of influenza—influence intent to vaccinate, risk perception, and knowledge. DESIGN: Survey with participants randomized to receive a simulated news article accompanied by one of the three graphics that communicated prevalence of influenza and number of influenza-related deaths. SETTING: International online survey. PARTICIPANTS: 16,510 adults living in 11 countries selected using stratified random sampling based on age and gender. MEASUREMENTS: After reading the article and viewing the presented graphic, participants completed a survey that measured interest in vaccination, perceived risk of contracting disease, knowledge gained, interest in additional information about the disease, and perception of the graphic. RESULTS: Heat maps and picto-trendlines were evaluated more positively than dot maps. Heat maps were more effective than picto-trendlines and no different from dot maps at increasing interest in vaccination, perceived risk of contracting disease, and interest in additional information about the disease. Heat maps and picto-trendlines were more successful at conveying knowledge than dot maps. Overall, heat maps were the only graphic to be superior in every outcome. LIMITATIONS: Results are based on a hypothetical scenario. CONCLUSION: Heat maps are a viable option to promote interest in and concern about infectious diseases.