Data visualizations tell a story. Stories move people.

The explosion of Space Shuttle Challenger in January 1986 is a classic example of disasters from of BAD data visualizations.

The night before the disaster, scientists had predicted the catastrophe. They tried to persuade their superiors to postpone the launch because the O-rings that sealed the bottoms of the Space Shuttle’s solid rocket boosters would fail in the cold temperatures predicted for next morning’s flight. Ultimately they were overruled and the launch countdown proceeded. 73 seconds into its flight, Space Shuttle Challenger exploded, instantly killing its 7 crew members.

Data visualization legend Edward Tufte argues in his book Visual Explanations that the engineers failed to communicate the dangers because data wasn’t presented in an easily digestible form. Sloppy typography, unnecessary icons of rockets obscuring key numbers, and performance data of the O-rings arranged by launch date rather than by the critical factor, temperature.

Tufte argues that this made it all but impossible for decision makers to envision that a launch in weather below 66 degrees probably would lead to O-ring failure.