6.
Process or Product Monitoring and Control
6.4. Introduction to Time Series Analysis 6.4.3. What is Exponential Smoothing?


Summary  
Exponential smoothing has proven to be a useful technique  Exponential smoothing has proven through the years to be very useful in many forecasting situations. It was first suggested by C.C. Holt in 1957 and was meant to be used for nonseasonal time series showing no trend. He later offered a procedure (1958) that does handle trends. Winters(1965) generalized the method to include seasonality, hence the name "HoltWinters Method".  
HoltWinters has 3 updating equations 
The HoltWinters Method has 3 updating equations, each with a constant
that ranges from 0 to 1. The equations are intended to give more weight
to recent observations and less weights to observations further in the
past.
These weights are geometrically decreasing by a constant ratio. The HW procedure can be made fully automatic by userfriendly software. 