Errors are part of the (web) service
Since its launch in November 2006, Lokad has been providing a programmatic access to its forecasts through the Lokad Web API. Since the very first day, we have done our best to ensure the best forecasting accuracy. Yet, the future may not always be accurately predicted based on the sole historical data.
It is far better to foresee even without certainty than not to foresee at all. Henri Poincaré in The Foundations of Science, 1946
This situation is typically dealt with through an estimation of the forecast error: in addition to the forecast itself, an estimate of the forecast error is also computed. For example, this is the suggested approach for safety stock calculation.
Thus, we have decided to extend the Web API with estimated forecast errors. For any forecasting task, it is now possible to retrieve the Mean Absolute Percentage Error, see GetMape and GetMapes web methods. The new version of the Web API stays fully compatible with the existing applications.