SemiStandardDev (Function)

The SemiStandardDev function calculates a standard deviation of values (based either on the population or a sample) above the mean or a standard deviation of values below the mean. See below for more information.

Syntax

SemiStandardDev(Price, Length, PopOrSample, DownsideOrUpside);

Returns (Double)

A numeric value containing the Semi Standard Deviation.

Parameters

Name	Type	Description
Price	Numeric	EasyLanguage expression (price, function, formula, etc.) used as the price in the standard deviation calculations.
Length	Numeric	The number of bars over which to calculate the standard deviation.
PopOrSample	Numeric	Pass in 1 for the entire population, or pass in 2 for a sample.
DownsideOrUpside	Numeric	Pass in 1 to calculate downside standard deviation; pass in 2 to calculate upside standard deviation.

Remarks

This function returns the standard deviation of data points that are below the mean (if 1 is passed in for the “DownsideOrUpside” input) or the standard deviation of data points that are above the mean (if 2 is passed in for the “DownsideOrUpside” input). The values from this function are sometimes used as a measurement of downside risk (for a long position) or upside risk (for a short position).

Example

Assigns to Value1 the sample type standard deviation of the Close over 21 bars for downside standard deviation (data points below the mean):

Value1 = SemiStandardDev(Close , 21, 2, 1);

Assigns to Value2 the entire population type standard deviation of the High over 21 bars for upside standard deviation (data points above the mean):

Value2 = SemiStandardDev(High , 21, 1, 2);