EWMA Volatility

September 29th, 2019, 01:30 PM

Hi, I'm looking for an Easylanguage function to calculate EWMA Volatility. Can anyone please help? Thanks

September 30th, 2019, 12:37 PM

Answering my question

Code

Function: _VolaEWMA

inputs: Price(NumericSeries), Len(NumericSimple) ;
variables: squared_log_ret(0);                                                  
                                                                                                                                                       
squared_log_ret = Square(Log(Price / Price[1])); 
_VolaEWMA = SquareRoot(252 * XAverage(squared_log_ret, Len));

October 3rd, 2019, 08:45 AM

I've watched quite a few youtube videos and read articles on EWMA.

The final result is supposed to give a volatility prediction for the next day. However it is far from clear what that means or how it can be tested.

The GARCH process is quite similar but supposedly better -

What is the GARCH Process
"The generalized autoregressive conditional heteroskedasticity (GARCH) process is an econometric term developed in 1982 by Robert F. Engle, an economist and 2003 winner of the Nobel Memorial Prize for Economics, to describe an approach to estimate volatility in financial markets. There are several forms of GARCH modeling. The GARCH process is often preferred by financial modeling professionals because it provides a more real-world context than other forms when trying to predict the prices and rates of financial instruments."

There is probably some application in quantitative finance and portfolio management for this but EWMA and GARCH methodologies seem totally irrelevant for short term trading.

EWMA Volatility

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EWMA Volatility