Judgement based forecasts are widely used in practice either alone or in conjunction with computer prepared forecasts. This study empirically examines the improvement in accuracy which can be gained from combining judgemental forecasts, either with other judgemental or with quantitatively...

Predictions of call center arrivals are a key input to staff scheduling models. It is, therefore, surprising that simplistic forecasting methods dominate practice, and that the research literature on forecasting arrivals is so small. In this paper, we evaluate univariate time series methods for...

A state-space seasonal time series model and a new seasonal decomposition algorithm, based on the Kalman filter, are introduced. The time series model is statistically equivalent to the multiplicative seasonal model, ARIMA (0, 1, 1)(0, 1, 1)_s, of Box and Jenkins. It is shown that the...