2021 Yes https://doi.org/10.1121/10.0005815 Wang, Lily M. North America Experimental Students Elementary (K-5) Middle/Jr High (6-8) High School (9-12) Noise Acoustic monitoring was conducted over 6 days in 220 U.S. K–12 classrooms. Speech and noise levels were analyzed using clustering methods to estimate signal-to-noise ratios. Findings support improving classroom acoustics to promote speech clarity and learning.