CONCERTGOERS, CRITICS, TEACHERS, AND PERFORMERS are often called upon to cast judgment on the performances they hear. Research to date has typically focused on the judgments themselves, with very few empirical studies of the processes and decisions that lead to these judgments. This paper details an investigation of time-dependent characteristics of performance evaluation. Thirty-three participants were played five recordings of a Bach Prelude and five of a Chopin Prelude. They rated the quality of each performance continuously, by moving a mouse cursor on a 7-point scale displayed on a computer screen, and using written scales. The results suggest that: the time taken to reach an evaluative decision was typically short (around 15––20 s); there was a significant difference between the initial and final ratings, with a tendency for ratings to improve as the performances progressed; and the largest revisions of opinion took place within the first minute of the performance.