The Positive Volume Index is calculated by adding to the index
the percentage change in value (of a market index or security price) only when the
volume has increased from the previous day. A rise in the indicator could be interpreted
as bullish. It can be useful to overlay a long period (for example, 52-week) moving
average of this indicator. A Positive Volume index above its moving average would
be a bullish signal. The bearish signal would be in force while the Positive Volume
Index was below its moving average. However, this indicator more reliably indicates
bull than bear trends.
Since this indicator was developed for use with market indices, you would be well
advised to experiment extensively with historical data before applying it to individual
securities as part of a trading system.
References
Colby and Meyers (1988). The Encyclopedia of Technical Market Indicators.
Dow Jones-Irwin.