If you measure the daily ranges between the low and the high you will be able to calculate inconstancy. If the daily range is large, then it is high. When the daily range is a little, then it is low. The Notis %V study contains 2 separate indicators. It divides market inconstancy into downward (DVLT) and upward (UVLT) parts. Both are places separately in the same window, and can be placed as an oscillator. The upward part compares the total inconstancy (UVLT + DVLT) and expressed as a percentage. This explains its name, %V.
Volatility can be a key to options trading. A right usage of market volatility can keep you away from the situations when your option still loses value even when the market shifts your way.