RSI vs Wilder's RSI Calculation

Discussion in 'Technical Analysis' started by OneTwoThree, Jul 20, 2016.

  1. I am having trouble getting a smoothed RSI. The below picture is from freestockcharts.com. The calculation uses this code.

    [​IMG]
    http://stackoverflow.com/questions/...th-index-using-some-programming-language-js-c

    This seems to be the pure RSI with no smoothing. How does a smoothed RSI get calculated? I have tried changing it to fit the definitions of the these two sites however the output was not correct.

    http://www.tc2000.com/tc2000help/Content/Indicators/RSI_and_Wilder_s_RSI.htm
    http://www.priceactionlab.com/Blog/2014/12/wilders-cutlers-and-harris-relative-strength-index/

    Can someone actually do the calculation with some sample data?


    [​IMG]
     
  2. Sergio77

    Sergio77

    RSI value depends on starting point and if you do not have enough data the calculations will not match.
     
  3. terr

    terr

    I don't think your calculation of RSI is correct.

    For one thing, it basically uses a variable-period (up to the total # of data points) MA, while RSI is supposed to use a fixed-period MA. Also, your calculation is equivalent to using an SMA, while the classic RSI uses EMA (and Wilder's RSI uses Wilder's EMA).

    Here are Medved Trader's RSI and Wilder's RSI (the bottom one uses Wilder's EMA) for the same period of the same stock as your chart:

    upload_2016-7-20_22-27-18.png

    Mike Medved
    http://www.medvedtrader.com
     
  4. YOu want to cacilate smoothed RSI, Just apply MA to RSI.

    RSI= 100-100/(1+sumGain/sumLoss);

    RSIma(i) = RSIma(i-1) + 2/(n+1)(RSI- RSIma(i-1))
    //n is smoothing bar period

    if you want to use Wilders smoothing (Wilders RSI) them EMA folrmula will be slightly different:

    RSIma(i) = RSIma(i-1) + 1/n * (RSI- RSIma(i-1))
    //n is smoothing bar period

    Smoothed RSI is less choppy and provudes better result wen compared to raditional RSI:
    http://www.marketvolume.com/stockstradingsystems/?d=55&aid=Smoothed-RSI-Simple-Trading-System
     
  5. terr

    terr

    Thanks for pointing the Cutlers and Harris variations for RSI. I added them to Medved Trader. Will be out in next beta.

    Mike Medved
    www.medvedtrader.com
     
  6. Trader13

    Trader13

    That pretty much sums up the answer.

    Wilder used his own version of a moving average calculation that is slower than both SMA and EMA, which might have been okay for slower moving markets at the time he published the RSI in 1978. But Wilder's original smoothing method has too much lag for today's faster markets, so current implementations of the RSI often use a standard EMA.

    Don't get hung up on the way a smoothed RSI was originally published. It was a different time with different markets. Just apply your moving average of choice to the RSI based on your modelling and testing. I think you'll find an EMA works best, but that judgement is ultimately yours to make.
     
  7. Sergio77

    Sergio77

    That is wonderful. Thanks. Will check it out.
     
  8. Sergio77

    Sergio77

    Looking forward to making some comparisons between standard, Cutlers and Harris variations of RSI.

    About the Price Action Lab software I know a hedge fund that runs about a dozen computer with it every day. The are pretty secretive about it but i figured out they are looking for micro patterns in many time frames. Then they use a neural network to select the best. Quite advance operation they have.
     
  9. Jerry030

    Jerry030

    It might be of interest to know that Wilder's RSI when analyzed statistically over decades and dozens of markets has been shown to have close to zero capacity to predict future market behaviour. However the RIS does generate some really cute wavy lines on the computer screen.

    On the other hand Wavelets generate equally cute lines and do have predictive capacity....go figure.

    http://vlab.ee.nus.edu.sg/~bmchen/papers/PhysicaA2015.pdf
     
    #10     Jul 30, 2016