We know that when forecasting the product hierarchy, reconciliation is invariably needed to make the sum of lower-level forecasts equate to the upperlevel forecasts. The authors argue that the traditional Bottom-Up, Top-Down, and Middle-Out procedures for reconciliation all fail to make best use...

Neelie Kroes, while antitrust commissioner for the EU, said, “In the current economic context, all companies are looking for cost-effective IT solutions. Systems based on open-source software are increasingly emerging as viable alternatives to proprietary solutions.” Stephan Kolassa and Rob...

Some traditional measurements of forecast accuracy are unsuitable for intermittent demand data because they can give infinite or undefined values. Rob Hyndman summarizes these forecast accuracy metrics and explains their potential failings. He also introduces a new metric-the mean absolute...

Authors Rob Hyndman and Andrey Kostenko discuss the bare minimum data requirements for fitting three common types of seasonal models: regression with seasonal dummies, exponential smoothing, and ARIMA. Achieving the requisite minimum numbers, however, does not ensure adequate estimates of...