Negative volume index and positive volume index
NVI and PVI are based on the accumulation method the absolute value depends on the starting date. The absolute values will be different in one year and 3 years charts. Because of this limitation, you cannot derive any conclusion based on its absolute value. Long term moving average normally or 200 days moving average is plotted on the positive volume index and negative volume index charts to identify the primary market trends.
The negative volume index usually remains above the long-term average during the bull market and positive volume index below the long term average during the bear market. there is 95% probability that a bull market is in progress if negative volume index has placed a verb its long term moving average. The probability of a bear market when a positive volume index is placed below its long-term moving average is 67%.
The positive volume index and negative volume index processing its own long term average can also give important signals. we have holidays in the positive volume index that will be below the long-term average during their market and therefore positive volume index going below the long term average can be treated as the starting point of a bear market. Confirmation by a positive volume index is useful for people who trade based on other technical indicators like 200 days moving average of price. For example nifty below its 200 days moving average during August and September of 2019. Since this is a bearer signal this would have triggered or sale, if one was using only that indicator however positive volume index, remained above its 200 day moving average and therefore indicated that bear market is it to be start and saved the trader from squaring off his position.