Outliers also can provide important clues. In an outbreak of thyrotoxicosis in 1985, most cases came from Luverne, Minnesota, and the surrounding areas. Only one case was identified in Sioux Falls, South Dakota, 60 miles away. Did this person ever go to Luverne? Yes. Was she a friend or acquaintance of any of the Luverne cases? Not really. What does she do when she goes to Luverne? Visit my father and buy the locally produced ground beef that he sells in his store. Aha! The hypothesis that the locally produced ground beef was the vehicle could easily be tested by