Holt-Winters Method with Missing Observations

The paper presents a simple procedure for interpolating, smoothing, and predicting in seasonal time series with missing observations. The approach suggested by Wright (Wright, D. J. 1986. Forecasting data published at irregular time intervals using extension of Holt's method. Management Sci. 32 499--510.) for the Holt's method with nonseasonal data published at irregular time intervals is extended to the Holt-Winters method in the seasonal case. Numerical examples demonstrate the procedure.