Outputs of an automatic probabilistic event detection system, such as a fact extraction system, a speech-to-text engine or an automatic character recognition system, are matched with comparable results produced manually or by a different system. This comparison allows statistical modeling of the run-time behavior of the event detection system. This model can subsequently be used to give supplemental or replacement data for an output sequence of the system. In particular, the model can effectively calibrate the system for use with data of a particular statistical nature.