The relative volatility index (RVI) was developed by Donald Dorsey, who truly understood that an indicator is not the holy grail of trading. The RVI is identical to the relative strength index, except it measures the standard deviation of high and low prices over a defined range of periods. The RVI can range from 0 to 100 and unlike many indicators that measure price movement, the RVI does an exceptional job of measuring market strength.
The relative volatility index was designed not as a standalone indicator, but as a confirmation for trading signals. The RVI is most widely used in conjunction with moving average crossover signals.
Below are the rules that Dorsey developed for valid buy and sell signals when using the RVI: