Student Test Scores Suffer from Even Subtle Background Noise

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Teachers do all they can to provide a productive learning experience for their students, but some factors are beyond their control and may actually be dragging down standardized test scores. According to research on third- and fifth-grade classrooms presented at the 162nd meeting of the Acoustical Society of America (ASA), fifth-grade students were found to have lower reading test scores in classrooms with higher background noise. A similar negative trend was observed between the fifth-grade language achievement test scores and background noise levels.

The noise the researchers measured and compared to test scores was not the expected cacophony of nearby traffic or occasional outbursts from unruly students. Instead the noise came from the steady droning and humming of the air conditioning and heating systems.

“Our research shows that many students are forced to learn and teachers are required to work in conditions that simply do not aid in the learning experience,” said Lauren M. Ronsse, now with the U.S. Army Engineer Research and Development Center in Champaign, Ill. She and her doctoral advisor Lily M. Wang of the University of Nebraska at Lincoln measured the background noise in 67 unoccupied third- and fifth-grade classrooms in a Nebraska public school district. The researchers were primarily interested in the noise produced by the ever-present heating and cooling systems in the schools. These systems produce a constant source of background noise that they believe could mask sounds, muddle oral communications, and interfere with comprehension during instructions. The sound measurements were specifically conducted in empty classrooms since design guidelines often specify desired unoccupied acoustic conditions. Higher levels of noise in unoccupied conditions are linked to higher noise levels when those rooms are occupied by students, since students have to express themselves more loudly to be easily heard.

In this study, the researchers placed a sound level meter at the center of each classroom. With the support of teachers and school administrators, they took a number of baseline readings to gauge the intrinsic noise of the air systems. The research went on for 5 months, from January through May 2010. It was typically conducted after the end of the school day, from 3:30 p.m. to 6 p.m.

After the measurements were completed, the researchers compared the background noise levels of the classrooms to the standardized student achievement scores. They observed statistically significant correlations among the fifth-grade students, though the negative effect was not observed among the third-grade students.

A previous study by the researchers suggested that the maximum allowable classroom background noise levels to reach Iowa state targets for student reading comprehension scores should be approximately 41 decibels, which is the noise level found in an average office setting. To reach the optimal Nebraska state targets for student reading scores, however, their new research indicates that the background noise in a classroom should be as low as 28 decibels, which is actually just above a whisper and quieter than the humming of a refrigerator.

“The results from these studies indicate that elementary schools should be built with building mechanical systems that are certainly quieter than 40 decibels in the classrooms to optimize student learning in the reading comprehension and language subject areas,” said Ronsse.