Charts
Negative Volume Index
The Negative Volume Index (NVI), as well as the Positive Value Index (PVI), indicator tracks the changes in the number of transactions, or trading volume, of an instrument. Price changes on decreasing trading volume are considered to be a positive indicator, while price changes during periods of increased trading volume are considered to be a negative indicator. The idea behid the indicator is that wellinformed traders are involved when trading volumes decrease, while increasing trading volumes can indicate a followthecrowd mentality.
The MVI displays what the "smart money" is doing; while the PVI tracks what the "notsosmart money" is doing.
Configuration Options
 Field: Price or combination of prices to use as the base for average calculations. Possible values include:
 Open
 High
 Low
 Close
 Adjusted Close
 HL/2 \( \left ( \frac{High + Low}{2} \right ) \)
 HLC/3 \( \left ( \frac{High + Low + Close}{3} \right ) \)
 HLCC/4 \( \left ( \frac{High + Low + Close + Close}{4} \right ) \)
 OHLC/4 \( \left ( \frac{Open + High + Low + Close}{4} \right ) \)
 Moving Average Type: Type of moving average to use in the calculations:
 Simple: Mean (average) of the data.
 Exponential: Newer data are weighted more heavily geometrically.
 Time Series: Calculates a linear regression trendline using the “least squares fit” method.
 Triangular: Weighted average where the middle data are given the most weight, decreasing linearly to the end points.
 Variable: An exponential moving average with a volatility index factored into the smoothing formula. The Variable Moving average uses the Chande Momentum Oscillator as the volatility index.
 VIDYA: An exponential moving average with a volatility index factored into the smoothing formula. The VIDYA moving average uses the Standard Deviation as the volatility index. (Volatility Index DYnamic Average).
 Weighted: Newer data are weighted more heavily arithmetically.
 Welles Winder:The standard exponential moving average formula converts the time period to a fraction using the formula EMA% = 2/(n + 1) where n is the number of days. For example, the EMA% for 14 days is 2/(14 days +1) = 13.3%. Wilder, however, uses an EMA% of 1/14 (1/n) which equals 7.1%. This equates to a 27day exponential moving average using the standard formula.
 Hull: The Hull Moving Average makes a moving average more responsive while maintaining a curve smoothness. The formula for calculating this average is as follows: HMA[i] = MA( (2*MA(input, period/2) – MA(input, period)), SQRT(period)) where MA is a moving average and SQRT is square root.
 Double Exponential: The Double Exponential moving average attempts to remove the inherent lag associated to Moving Averages by placing more weight on recent values.
 Triple Exponential: TBD
 Simple
 Exponential
 Time Series
 Triangular
 Variable
 VIDYA
 Weighted
 Welles Winder
 Hull
 Double Exponential
 Triple Exponential
 Period: Number of bars to use in the calculations.
 Color Selectors: Colors to use for graph elements.
 Display Axis Label: Whether to display the most recent value on the Y axis.
Formula
Negative volume index is calculated as follows:

If today's volume is less than yesterday's volume:
\[ NVI = NVI_\text{yesterday} + \left( \frac {FieldPrice  FieldPrice_\text{yesterday}}{FieldPrice_\text{yesterday}} \times NVI_\text{yesterday} \right )\]

Otherwise:
\[ NVI = NVI_\text{yesterday} \]