We present our tracking system for the 1998 Topic Detection and Tracking project (TDT-2). This project addresses multiple sources of information in the form ofboth text and speech from newswire, radio and television news broadcast programs. Our tracking system isprobability based and we successfully solve the problemof score normalization across topics with a simple buteffective solution. Tested on the 20K TDT-2 stories collected between March and April 1998, our tracking systemachieves a performance of 1.5% miss error (on closed cap-tion and newswire) and 3.0% miss error (on automaticspeech recognition output and newswire) at the cost of0.1% false alarm error. In the 1998 TDT-2 evaluation,our tracking system was ranked the best with the officialtopic-weighted Ctrack measure of 0.0056. We observedthat there was no degradation in tracking performancedue to the speech recognition errors.