Relative Vigour Index (RVI). Ehlers

Relative Vigor Index - RVI
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An indicator used in technical analysis that measures the conviction of a recent price action and the likelihood that it will continue. The RVI compares the positioning of a security's closing price relative to its price range, and the result is smoothed by calculating an exponential moving average of the values.

The RVI indicator is calculated in a similar fashion to the stochastic oscillator, but the vigor index compares the close relative to the open rather than to the low.
Traders expect the RVI value to grow as the bullish trend gains momentum because in this type of environment, a security's closing price tends to be at the top of the range while the open is near the low of the day.

Usage Example: investopedia.com/ask/answers/012115/how-do-i-use-relative-vigor-index-rvi-create-forex-trading-strategy.asp