In which Lt is the new smoothed value; ˛ is the smoothing constant for the data (0 ≤ ˛ ≤ 1); yt is the new observation or actual value of series in period t; is the smoothing constant for estimating the trend (0 ≤ ≤ 1); Tt is the trend estimate in period t; h is the periods to be forecast;ˆyt+his the forecast for h periods into the future