The Mass Index indicator, developed by Donald Dorsey, uses the bar range to identify trend reversals based on range expansions. It is more of a volatility indicator as it does not have a directional bias. It identifies trending and congession areas, which can occur before change in trend.
\[EMA_{1} = 9-period\;EMA\;of\;the\;range\;(H-L)\]
\[DEMA_{1} = 9-period\;EMA_{1}\]
\[EMA Ratio = \frac{EMA_{1}}{DEMA_{1}}\]
\[MI = 25-period\;sum\;of\;the\;EMA\;Ratio\]