Measuring Improvement in Forecast Accuracy: A Case Study

Over the past 15-20 years, improvements in forecasting methods, deepening practical experience, and increasing computing power should have allowed companies to significantly improve their forecasting accuracy. In this paper Robert Rieg examines the changes in forecasting accuracy of a large automobile manufacturer between 1991 and 2005. His analysis shows how a company can examine its track record over time and emphasizes the need to distinguish internal from external factors that impinge on forecasting accuracy. Copyright International Institute of Forecasters, 2008