# Exponential Standard Deviation Bands

The AIQ code based on Vitali Apirine’s article in the 2017 issue of Stocks & Commodities magazine, “Exponential Standard Deviation Bands”

Editor note: “Author Vitali Apirine presented a method intended to help traders see volatility while a stock is trending. These bands, while similar to Bollinger Bands, are calculated using exponential moving averages rather than simple moving averages. Like Bollinger Bands, they widen when volatility increases and narrow as volatility decreases. He suggests that the indicator can be used as a confirming indication along with other indicators such as the ADX. Here’s an AIQ Chart with the Upper, Lower and Middle Exponential SD added as custom indicators.”

To compare the exponential bands to Bollinger Bands, I created a trend-following trading system that trades long only according to the following rules:
1. Buy when there is an uptrend and the close crosses over the upper band. An uptrend is in place when the middle band is higher than it was one bar ago.
2. Sell when the low is less than the lower band.
Figure 8 shows the summary test results for taking all signals from the Bollinger Band system run on NASDAQ 100 stocks over the period 12/9/2000 to 12/09/2016. Figure 9 shows the summary test results for taking all signals from the exponential band system on NASDAQ 100 stocks over the same period. The exponential band system improved the average profit per trade while reducing the total number of trades.

FIGURE 8: AIQ. Here are summary test results for taking all signals from the Bollinger Band system run on NASDAQ 100 stocks over the period 12/9/2000 to 12/09/2016.

FIGURE 9: AIQ. Here are summary test results for taking all signals from the exponential band system run on NASDAQ 100 stocks over the period 12/9/2000 to 12/09/2016.
and is also shown here:
!Exponential Standard Deviation Bands
!Author: Vitali Apirine, TASC February 2017
!Coded by: Richard Denning 12/11/2016
xlen is 20.
numSD is 2.

!INDICATOR CODE:
ExpAvg is expavg([close],xlen).
Dev is [close] – ExpAvg.
DevSqr is Dev*Dev.
SumSqr is sum(DevSqr,xlen).
AvgSumSqr is SumSqr / xlen.
ExpSD is sqrt(AvgSumSqr).

!UPPER EXPONENTIAL SD BAND:
UpExpSD is ExpAvg + numSD*ExpSD.  !PLOT ON CHART

!LOWER EXPONENTIAL SD BAND:
DnExpSD is ExpAvg – numSD*ExpSD.   !PLOT ON CHART

!MIDDLE EXPONENTIAL SD BAND:
MidExpSD is ExpAvg.

!BOLLINGER BANDS FOR COMPARISON:
DnBB is [Lower BB].  !Lower Bollinger Band
UpBB is [Upper BB].  !Upper Bollinger Band
MidBB is simpleavg([close],xlen). !Middle Bollinger Band
!REPORT RULE TO DISPLAY VALUES:
ShowValures if 1.

!TRADING SYSTEM USING EXPPONENTIAL SD BANDS:
UpTrend if MidExpSD > valresult(MidExpSD,1).
BreakUp if [close] > UpExpSD.
BuyExpSD if UpTrend and BreakUp and valrule(Breakup=0,1).
ExitExpSD if [Low] < DnExpSD.  ! or UpTrend=0.