The PVT can be considered to be more accurate than the OBV index in that the amount of volume apportioned each day is directly proportional to the underlying price action. So then, Large Moves account for large moves in the Index and small moves will account for small moves in the Index. This way the PVT can be seen to almost mirror the underlying market action, however as shown above, divergence can occur, and it is this divergence that is an indicator of possible future price action.