Price volume correlation is an effective statistical study in the field of stock market. Price and volume should always be correlated to validate any trending moves.
If the price is increasing along with increase in volume it is a valid bull trend. If the price is decreasing along with increase in volume it is valid bear trend.
Anything other than that is a pull back. Dot!!
For more info check the video about using this in my You tube channel "FIG learn market the right way"