This project seeks to determine what relationship, if any, exists between background noise levels in elementary classrooms due to the building mechanical
systems and student performance on achievement tests. Previous research in classroom acoustics has clearly identified that lower background noise levels
result in higher speech intelligibility which is crucial for the learning process; however, there is a lack of data correlating lower noise levels to improved student achievement scores. For this study, background noise level measurements were made in 14 elementary schools in a public school system in Council Bluffs, Iowa, USA.

The measurements were made in unoccupied classrooms with the central building mechanical systems activated. Second and fourth-grade classrooms were included in the study, which typically contain 7 to 8 and 9 to 10 year-old students, respectively. The unoccupied noise levels measured in the analyzed classrooms range from 36 – 50 dBA, none of which meets the background noise level recommendation of 35 dBA or less specified for classrooms in ANSI S12.60-
2002(R2009). These measured background noise levels have been correlated to reading comprehension and math standardized achievement test scores from students in the surveyed classrooms. Poverty rates were used as a control variable for the correlation analyses to factor out some of the socio-economic differences among the students. ANOVA and regression analyses were also performed to determine if learning for the younger and older students was impacted similarly by mechanical system noise and what background noise level should be attained in classrooms to meet state learning achievement goals. The results from this study show that, for the elementary school system tested, lower student reading comprehension scores were significantly related to higher background noise levels from building mechanical systems.