The process of score following requires that the automated follower be capable of making robust decisions during a performance, especially in light of the number of errors that need to be accounted for between the live performer and the follower. Based on the concept of variable-length signatures for monophonic symbolic input, we define a causal method for tracking score location. The signature lengths are calculated prior to performance based on their novelty in a predetermined locality within the score. The score following model is event based, but it also uses an inertial mechanism to pace itself in the presence of contradictory information. Results are derived from the output of the score follower using a graphical display that depicts the associations between performed notes and the score. This display aids in visual evaluation of the performance of the score following process and, specifically, its capability of recovery following any of the performance aberrations.