Classroom Size and Student Performance – Know the Facts


A wide range of studies in both the UK (by organisations such as BATOD) and USA conclude that classroom size and student performance work against each other adversely.


Besides the obvious factors which come into play (for example, the more students there are, the less contact time there is between the individual student and the teacher), bigger classrooms often mean that poor acoustics are prevalent.


If this information is widely available, why are schools not upgrading their classrooms to include all students? To quote Dr John Erdreich: We would never teach reading in a classroom without lights. Why then do we teach in ‘acoustical darkness’. Speaking to a class, especially of younger children, in a room with poor acoustics, is akin to turning out the light“.


Speech Intelligibility


Speech intelligibility refers to how we understand others when communicating. There are four physical factors affecting speech intelligibility: room geometry, the signal to noise ratio, background noise levels and reverberation time.


Elements of Speech Intelligibility


In addition to this, it is important to consider the individual student. Not everyone communicates or understands speech in the same way.


Populations most affected by poor acoustic conditions in classrooms include:


  • Young, <13-15 year old students
  • Students with a hearing loss
  • Those with articulation and language disorders
  • Non-native language speakers – “English as a foreign language”
  • Individuals with auditory processing disorders


Room Geometry


Room geometry relates to the shape of a classroom and how students receive sound throughout the space. Logically, sound is louder the nearer you are to the source of the sound. The drop off in sound follows the inverse square law.


Inverse Square Law


  • Sound intensity reduces in proportion to the square of the distance from the sound signal, irrespective of the sound’s directivity – for example, twice the distance means ¼ of the sound intensity
  • Sound spreads out and gets weaker as energy is spread more thinly.
  • At the sound source there is constant power.
  • Just as it is difficult to see at a distance, it is difficult to hear at distance


Inverse Square Law


Classroom Guidelines


The minimum standards for sound and acoustic regulation at school are set out in Building Bulletin 93 (BB93). The regulations apply to all new school buildings built since 2003 in England and Wales. The regulation was introduced in order to regulate the acoustic design in schools to reflect a general recognition, supported by research, that teaching and learning are acoustically demanding activities. In particular there is a consensus that low ambient noise levels are required, particularly in view of the requirements of the Special Educational Needs and Disability Act 2001, for integration of children with special needs in mainstream schools.


The Disability Discrimination Act requires schools to:


  • not  treat disabled pupils as “less favourable’
  • make reasonable adjustments to ensure that disabled pupils are not at a substantial disadvantage
  •  draw up plans to show how, over time, they will increase access to education for disabled pupils through school accessibility plans


The classroom recommendations by BATOD and ASHA are listed below.


classroom recommendations by BATOD


By following the guidelines set out above you will be up to date with the minimum modern classroom standards. We hope that you found this article informative and if you’d like to receive an acoustic health check in your school or classroom, feel free to contact us.


See the sources below for further reading on creating the optimal classroom and ensuring that your child receives the education that he/ she deserves:


Is Your Child Able to Hear at School? – Questions for Parents

Simple Steps to Better In-Class Acoustics


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