WOULD you be surprised to learn that many imprisoned people have serious personality disorders, such as psychopathy? Probably not. But I'd confidently predict you would be surprised to find that popular methods to predict the risk of reoffending to aid decisions on sentence length and release date for such people are no better than a coin toss.
This is the worrying verdict on long-established tools to assess the risk of violent reoffending, the latest blow to their utility [New Scientist, 09 December 2013 by Seena Fazel]