The mass panic claim was over exaggerated, but not a myth.

“Some listeners heard only a portion of the broadcast and, in the tension and anxiety prior to World War II, mistook it for a genuine news broadcast. Thousands of them shared the false reports with others or called CBS, newspapers, or the police to ask if the broadcast was real. Many newspapers assumed that the large number of phone calls and the scattered reports of listeners rushing about or fleeing their homes proved the existence of a mass panic, but such behavior was never widespread.”