It used to be that an MD or Ph.D. would predict future dangerousness based almost solely on their knowledge of the person, without any formal assessment. Much of the time, this resulted in client's being released from, or kept in, supervised settings. When this method of risk prediction was studied, it was found that it was about as good as flipping a coin in terms of predicting future dangerousness. This finding led to a revolution in developing predictive risk factor tools that, today, allow for more accurate characterization of risk and its management.