What was the challenge?
The US Global Change Research Program (USGCRP) makes climate change data publicly available, including a set of indicators. The effectiveness of indicators for informing the public and decision makers about climate change depends in part on how easy it is to understand those indicators.
What did we do?
Using a representative online survey, weidentified the two USGCRP indicators that had the lowest understandability rates - the Annual Greenhouse Gas Index, and the Annual Heating and Cooling Degree Days. We then redesigned these two indicators by eliminating axes, changing titles, and modifying the graphs. A second online survey asked new samples of 75-100 respondents the same questions to test whether design changes had an effect on understandability.
What did we learn?
Indicator effectiveness is best achieved through clarity of the visual key message rather than increased complexity in a single graphic. However, not all changes aimed at indicator simplicity or clarity result in significant improvements in understandability.