Data, information, and knowledge
The 1854 cholera epidemic case is a good example for understanding the differences between data, information, and knowledge. The data that Dr. Snow used, the locations of cholera outbreaks and water pumps, was already available. But the connection between them had not yet been discovered. By plotting both datasets on the same city map, he was able to determine that the pump at Broad street and Cambridge street was the source of the contamination. That connection was new information. That finally led to the new knowledge that the disease is transmitted by foul water, and thus the new knowledge on how to prevent the disease.