Technical Indicator for Trading. Volume Strength Index (VSI)

The Volume Strength Index (VSI) is a momentum volume oscillator that measures change of buying and selling pressure. VSI applies the Wilder's RSI formula to positive/negative volume values. VSI rises when volume on up days outpaces volume on down days. Conversely, VSI falls when volume on down days is stronger then volume on up days .
It can be used with RSI on the same graph to increase signal robustness.