Mass index

The mass index is an indicator, developed by Donald Dorsey, used in technical analysis to predict trend reversals. It is based on the notion that there is a tendency for reversal when the price range widens, and therefore compares previous trading ranges (highs minus lows). The mass index is an indicator, developed by Donald Dorsey, used in technical analysis to predict trend reversals. It is based on the notion that there is a tendency for reversal when the price range widens, and therefore compares previous trading ranges (highs minus lows). Mass index for a commodity is obtained by calculating its exponential moving average over a 9-day period and the exponential moving average of this average (a 'double' average), and summing the ratio of these two over a given number of days (usually 25).