# Charts

## Mass Index (MI)

### Description

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.

### Formula

$EMA_{1} = 9-period\;EMA\;of\;the\;range\;(H-L)$

$DEMA_{1} = 9-period\;EMA_{1}$

$EMA Ratio = \frac{EMA_{1}}{DEMA_{1}}$

$MI = 25-period\;sum\;of\;the\;EMA\;Ratio$