The M4 Forecasting Competition-Takeaways for the Practitioner

Should practitioners care about the M4? Does it reflect any of the complex realities faced by business forecasters? Or was it just a scholarly exercise, of interest only to forecasting academics? The M4 Forecasting Competition involved 61 competitors and benchmarks forecasting 100,000 time series with frequencies ranging from hourly to yearly. The competition led to a wealth of analysis and commentary on the relevance and implications of the results, including publication of 35 articles in a dedicated issue of the International Journal of Forecasting guest edited by Spyros Makridakis and Fotios Petropoulos. Here, Mike Gilliland provides background history and motivation for the M4, competition results, and important takeaways for business forecasting practitioners.