T his article examines the effects of composition length, familiarity, and likeability—as well as the location of performance errors—on the process of forming performance quality ratings. Five piano works by Chopin and a twentieth-century composer were chosen to vary by length and familiarity. Three of these pieces were then manipulated to contain performance errors in the opening material, and two of those the same error at the recapitulation. Forty-two musicians provided continuous quality evaluations and final quality ratings of the performances, hearing one version of each piece. The results showed that familiarity had no effect within works of a well-known composer, but times to first and final decision were significantly extended for an unfamiliar work of an unfamiliar composer. A shorter piece led to a shorter time to first decision. An error at the beginning of a performance caused a shorter time to first decision and lower initial and final ratings, where the same error at the recapitulation did not have a significant effect on the final judgment, despite causing a temporary negative drop. These findings demonstrate how evaluators’ knowledge of a work can affect their rating process and the importance of making a strong first impression in performance.