The primary purpose of this study was to investigate expertise-related differences in the evaluation of moment-to-moment rehearsal achievement. Nonmusic majors, music education majors, and expert music teachers (N = 60) listened to 18 "before" and "after" pairs of rehearsal trials of various high school bands in their pursuit of proximal rehearsal goals, or targets. These pairs of rehearsal trials ("dyads") were presented to participants on audio compact discs without evidence of the band directors' intervening rehearsal procedures. The performance quality of the ensembles heard on the recordings was either high or low, and the targets they pursued addressed "Tone Quality/Intonation," "Musicianship/Expressiveness," or "Rhythm/Articulation." The dependent measure was participants' evaluation of the extent of improvement heard within each dyad. A significant main effect was found for listener expertise, with experts evaluating ensembles' achievement on these targets most critically (i.e., lower), and with nonmajors offering the highest evaluation scores. No main effect on evaluation scores was found for ensemble performance quality. Results suggest that expert music teachers exercise judgments about moment-to-moment rehearsal achievement according to an internalized standard rather than to the immediately preceding rehearsal trial. Findings are discussed in consideration of the Model of Expert Teaching (Berliner, 1986).