Recently (1980's), interest has developed in what are called robust regression and outlier detection techniques, Ref [1]. Regression techniques are now defined by a measure called the "breakdown point". The breakdown point is loosely defined as the smallest amount of bad data points that can cause the regression solutions to take on values arbitrarily far from their true values. Unfortunately the Least Squares technique has a breakdown point of 1/N. In other words only one bad data point can significantly change the computation of the velocity or slope of a straight line. The median of a set of numbers has a breakdown point of 50% . This is because when 50% of the numbers are bad then there is no way of telling which are the bad numbers and which are the good numbers. 50% is the highest breakdown point.
Recently Siegel Ref[2], in his paper "Robust regression using repeated medians", introduced a technique for finding the slope that has a 50% breakdown point. The repeated median is also described in Ref [1].
The mathematical formula for the Repeated Median is:
Slope(t) =median i (i=1 to N) {median i≠j (j=1 to N) [(price(j)-price(i))/(j-i)] }
The repeated median slope is used to create a system. For a straight line the velocity is equal to the slope. The repeated median velocity has the advantage that it is a natural random price noise inhibitor. We can create a system such that unless the repeated median velocity using N past price bars is greater than some threshold we will not buy or sell. A large percentage of price noise generates a lot of back and forth movements of small magnitudes over a short period of time. With a lot of systems this back and forth movement creates many false buy and sell signals. However using the repeated median velocity over N past prices, we can filter out many of the small price noise movements by requiring that the velocity to be greater than some threshold before we act.
References
The Repeated Median Velocity System Input Parameters
My working paper on the Robust Repeated Median Velocity System can be found on the Papers Page
Product Description
For TradeStation, Multicharts all of the EasyLanguageâ„¢ strategy and indicator codes are directly importable into your choice of TS9 or MC and are fully disclosed. There are no locks of any kind on the EasyLanguage source code. The C++ DLL code is not disclosed. The Input parameters to the strategy and indicator are changeable and optimizable so that the user can develop his own parameter set on his price series and time frame of interest. Although the system results will give parameters for the intraday or daily futures the system was tested on, the user can easily use this system on any tradeable or on any time frame.
For NeuroShell Trader/DayTrader Pro, the Trading Strategy and Indicators are directly imported into NeuroShell via a special setup exe file and are fully disclosed in the Indicator wizard "MA_KeyTrSys" category and in the Trading Strategy Wizard "MA_KeyTrSys" directory. The C++ DLL code is not disclosed. The Input parameters to the strategy and indicator are changeable and optimizable so that the user can develop his own parameter set on his price series and time frame of interest. Although the system results will give parameters for the intraday or daily futures the system was tested on, the user can easily use this system on any tradeable or on any time frame.
The accompanying page manual consists of:
In addition The Robust Repeated Median Velocity system has its exact duplicate in indicator form which is displayable on the price chart, so that the user can visually see how the buy and sell signals occur.
For TradeStation, MultiCharts The Robust Repeated Median Velocity System™ is one of the 6 systems included in the Key Daily &Intraday Trading Systems package. The Key Daily &Intraday Trading Systems package is being offered through Meyers Analytics L.L.C. for $395. Shipping via Email consists of a zip file containing the Manual in Adobe PDF format, ELD file and DLL file.
For NeuroShell Trader/DayTrader Pro, The Robust Repeated Median Velocity System™ is one of the 6 systems included in the Key Daily &Intraday Trading Systems package.. The Key Daily &Intraday Trading Systems package is being offered through Meyers Analytics L.L.C. for $395 . Shipping via Email consists of a zip file containing the Manual in Adobe PDF format and the MA-KeyTrSysSetup.exe setup file.