

The EWMA can also be used in a simple crossover strategy, where a buy signal is generated when the price crosses the EWMA from above, and a sell signal is generated when the price crosses the EWMA from below.Īnother application of the EWMA in technical analysis is that it can be used as support or resistance levels. A buy signal is generated when the NVI crosses above its 250-day EWMA. A well-known example is the Negative Volume Index (NVI), which is used in conjunction with its EWMA. It may not be used directly, but it is used in conjunction with other indicators to generate trading signals. The EWMA is widely used in technical analysis. Applications of the EWMA Technical Analysis Naturally shorter the lookback period – more closely, the EWMA – tracks the original time series. N = number of days for which the n-day moving average is calculatedįor example, a 15-day moving average’s alpha is given by 2/(15+1), which means alpha is 0.125.To compute the moving average, we first need to find the corresponding alpha, which is given by the formula below: The EWMA can be calculated for a given day range like 20-day EWMA or 200-day EWMA. The fact is illustrated in the chart below, which plots the weights of observation as k increases for different choices of the parameter alpha. In other words, as we go back further in history, the weight becomes smaller. Since alpha is between 0 and 1, the weight becomes smaller as k becomes larger. The equation can be rearranged to show that the EWMA t is the weighted average of all the preceding observations, where the weight of the observation r t–k is given by: The process continues until we reach the base term EWMA 0.

It can be further expanded by going back another period: The above equation can be rewritten in terms of older weights, as shown below: The EWMA’s recursive property leads to the exponentially decaying weights as shown below: The EWMA is a recursive function, which means that the current observation is calculated using the previous observation.
#Cross weight formula series
