A key aspect of risk intelligence is recognizing the limits to your knowledge. People’s judgment of risks is deeply compromised by psychological biases. One of the most pervasive of these is a phenomenon called the favourite long-shot bias, first observed by the American Psychologist Richard Griffith in 1949. Since then, numerous studies have found evidence of the bias at racetracks and other sports betting markets all around the world. Indeed, it is probably the most discussed empirical regularity in sports gambling markets, and the literature documenting it now runs to well over a hundred scientific papers.