Hierarchical Multilevel Approaches of Forecast Combination

In this paper the approach of combining predictions is used to benefit from the advantages of forecasts predicting on different levels, to reduce the risks of high noise terms on low level predictions and overgeneralization on higher levels. The presented experimentally compared approaches of combining seasonal airline demand forecasts differ concerning input decomposition, multilevel structures, combination models and kinds of aggregation. Significant forecast improvements have been obtained when using multilevel, hierarchical structures.