"Risk models are models of uncertainty, engineered for some purposes. They are educated guesses and hypotheses assessed and valued in terms of well-defined future states and their consequences. They are engineered to predict, to manage countable and accountable futures and to provide a frame of...

The Markov model showed only slight predictive advantage over the no-change model for short-term forecasting of supermarket choices for a sample of 45 families. While this does not imply a blanket rejection of the Markov technique for forecasting, it is important to recall that this case held to...