Forecasting accuracy is a critical factor for, among other things, reducing costs and providing better customer service.
Yet the knowledge and experience available for improving such accuracy for specific situations is not always utilized. The consequence is actual and/or opportunity losses, sometimes of considerable magnitude. Empirical studies in the field of forecasting have compared the post-sample forecasting accuracy of various methods so that their performance can be determined in an objective, measurable manner.
The M Competitions are such empirical studies that have compared the performance of a large number of major time series methods using recognized experts who provide the forecasts for their method of expertise. Once the forecasts from each expert have been obtained they are evaluated and compared with those of the other experts as well as with some simple methods used as benchmarks. Forecasting competitions assure objectivity while also guaranteeing expert knowledge.
For a complete description of the M Competitions see Wikipedia.